Pipe joint structure and assembly method of the same

Abstract

To provide a pipe joint structure which enables reduction of a risk that a nut comes loose during use of a pipe, and to provide an assembly method of the pipe joint structure.SOLUTION: A pipe joint structure 1 includes: a first pipe 20 or a second pipe 21; a joint body 30 into which an end of the first pipe 20 or the second pipe 21 is inserted; nuts 50 each of which is screwed into the joint body 30 to fasten the first pipe 20 or the second pipe 21 to the joint body 30; and a loosening inhibition ring 40 provided at a joint groove part 32 formed at an outer diameter part of the joint body 30. The nut 50 has a nut groove part 52 in which the loosening inhibition ring 40 is housed in an inner diameter part. The loosening inhibition ring 40 has: a ring shaped part 42 extending in a circumferential direction; and a plurality of protruding parts 44 protruding to the radial outer side. When the nut 50 fastens the first pipe 20 or the second pipe 21 to the joint body 30, the protruding parts 44 of the loosening inhibition ring 40 are housed in the nut groove part 52 of the nut 50. Thus, the structure can reduce a risk that the nut comes loose during use of the pipe.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a pipe joint structure and an assembly method thereof. [Background technology]

[0002] A known example of an expansion type fitting is the one described in Patent Document 1, which involves expanding (expanding) the area near the end of a stainless steel pipe used for cold and hot water supply piping to form an expanded section, then inserting the pipe end into the fitting body and tightening a nut over the expanded section, thereby sealing the fitting body with water and preventing the pipe from coming loose. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-318459 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the pipe expansion joint described in Patent Document 1 had the problem that if the nut was not tightened properly or if excessive vibration, pressure changes, thermal contraction, or thermal expansion occurred during use of the piping, the nut could loosen, reducing the force pressing the stainless steel pipe against the sealing material, which could result in fluid leaking from the gap between the stainless steel pipe and the joint body.

[0005] The present invention has been made to solve the above-mentioned problems, and aims to provide a pipe joint structure and an assembly method thereof that can reduce the possibility of nuts loosening during use of the pipe. [Means for solving the problem]

[0006] The pipe fitting structure of the present invention comprises a pipe, a pipe fitting into which an end of the pipe is inserted, a nut that screws onto the pipe fitting and fastens the pipe and the pipe fitting, and a loosening prevention member provided in a fitting groove formed on the outer diameter portion of the pipe fitting, wherein the nut has a accommodating portion in which the loosening prevention member is accommodated in the inner diameter portion, and the loosening prevention member has a ring-shaped portion extending circumferentially and a plurality of protruding portions that protrude radially outward, and when the nut fastens the pipe and the pipe fitting, the protruding portions of the loosening prevention member are accommodated in the accommodating portion of the nut.

[0007] In addition, the nut accommodating portion may have an edge portion that protrudes radially inward at the end on the side that moves when the nut is tightened, and when the nut fastens the pipe and the pipe fitting, at least some of the multiple protrusions of the loosening prevention member may engage with the edge portion. Furthermore, the plurality of protruding portions of the loosening inhibiting member may have a protruding length in the radially outward direction that is different from that of at least one other protruding portion. The ring-shaped portion of the loosening restricting member may have a plurality of notches. The annular portion of the loosening inhibiting member may have a flange portion that protrudes radially outward, and the protrusion may be provided on the flange portion. The ring-shaped portion of the loosening inhibiting member may have a constant width along the axial direction. The protrusion of the loosening inhibiting member may be provided at the end of the annular portion.

[0008] A method for assembling a pipe fitting structure according to the present invention includes a pipe, a pipe fitting into which an end of the pipe is inserted, a nut that screws onto the pipe fitting and fastens the pipe and the pipe fitting, and a ring-shaped loosening preventive member that is provided in a fitting groove formed on the outer diameter portion of the pipe fitting, the nut having a accommodating portion in its inner diameter portion where the loosening preventive member is accommodated, the accommodating portion having an edge that protrudes radially inward at an end that advances when the nut is tightened, and the loosening preventive member having a plurality of protrusions that protrude radially outward, the method comprising the steps of: when the nut is tightened onto the pipe fitting and the nut is in a first position, the protrusions of the loosening preventive member are pressed by the edge of the accommodating portion of the nut; and when the nut is further tightened and is in a second position, the protrusions of the loosening preventive member are accommodated in the accommodating portion. [Effects of the Invention]

[0009] According to the present invention, the nut of the pipe fitting structure has an accommodation portion in its inner diameter portion in which a loosening prevention member is accommodated, and the loosening prevention member has a ring-shaped portion extending circumferentially and a plurality of protrusions protruding radially outward, and when the nut fastens the pipe and the pipe fitting, the protrusions of the loosening prevention member are accommodated in the accommodation portion of the nut, thereby reducing the possibility of the nut loosening while the pipe is in use.

[0010] Furthermore, according to the present invention, the method for assembling a pipe fitting structure includes a step in which, when the nut is tightened onto the pipe fitting and the nut is in a first position, the protrusion of the loosening prevention member is pressed by the edge of the nut's accommodating portion, and a step in which, when the nut is further tightened and in a second position, the protrusion of the loosening prevention member is accommodated in the accommodating portion, thereby reducing the possibility of the nut loosening during use of the pipe. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is an exploded half-sectional view of a pipe joint structure according to a first embodiment of the present invention. [Figure 2] 2 is a side view of the loosening restricting ring shown in FIG. 1, viewed in a direction along the central axis. [Figure 3]FIG. 3 is a perspective view of the loosening restricting ring shown in FIG. 2. [Figure 4] FIG. 2 is a half-sectional view of the pipe joint structure when the nut is temporarily fastened to the joint body. [Figure 5] FIG. 4 is an enlarged cross-sectional view of a second pipe, a joint groove portion, a loosening prevention ring, and a nut groove portion. [Figure 6] 2 is a cross-sectional view of the pipe joint structure taken along line A-A'. FIG. [Figure 7] FIG. 10 is an enlarged cross-sectional view of the second pipe, the joint groove, the loosening prevention ring, and the nut groove during the process of finally tightening the nut. [Figure 8] FIG. 10 is a half-sectional view of the pipe joint structure when the process of fully tightening the nut is completed. [Figure 9] 9 is an enlarged cross-sectional view of the second pipe, the joint groove, the loosening preventive ring, and the nut groove shown in FIG. 8. [Figure 10] 10 is a side view of a loosening inhibiting ring according to a second embodiment of the present invention, viewed in a direction along the central axis. FIG. [Figure 11] FIG. 11 is a perspective view of the loosening restricting ring shown in FIG. [Figure 12] 10 is a side view of a loosening inhibiting ring according to a third embodiment of the present invention, viewed from a direction along the central axis. FIG. [Figure 13] FIG. 13 is a perspective view of the loosening restricting ring shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] Embodiment 1 Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional exploded view of one side of a pipe joint structure according to a first embodiment of the present invention. The pipe joint structure 1 is used in piping equipment installed in commercial facilities, homes, factories, etc., and includes a first pipe 20, a second pipe 21, and a joint body 30 connecting these pipes. The first pipe 20 and the second pipe 21 are metal pipes through which fluids, including various gases or liquids such as refrigerants, high-temperature or low-temperature gases, hot water, or cold water, flow. The first pipe 20 has a first expanded pipe section 22 with an expanded diameter, and the second pipe 21 has a second expanded pipe section 23 with an expanded diameter. The first expanded pipe section 22 and the second expanded pipe section 23 are formed by expanding the diameter of portions of the first pipe 20 and the second pipe 21 using a known expanding tool. The first pipe 20 and the second pipe 21 can be formed from any metal material, such as stainless steel, copper, or an aluminum alloy.

[0013] The joint body 30 is a tubular joint made of any metal material, such as stainless steel, copper, or aluminum alloy. The joint body 30 has a protruding portion 31 that protrudes radially outward at the center of the central axis. Ring-shaped joint grooves 32 are formed on both sides of the protruding portion 31. In the following description, the direction in which the radial central axes of the joint body 30, the first pipe 20, and the second pipe 21 extend is referred to as the X direction. In the following description, the X, Y, and Z directions are mutually orthogonal directions. Specifically, the Z direction is the vertical direction, and the X and Y directions are horizontal directions orthogonal to the vertical direction. The Z direction is referred to as the height direction, and the higher side in the Z direction is referred to as the upper side and the lower side in the Z direction is referred to as the lower side. A male thread portion 33 is provided adjacent to the joint groove 32. The joint groove 32 has a smaller outer diameter than the male thread portion 33 and is formed in a perfect circle when viewed along the X direction. Furthermore, an end portion 34 of the joint body 30 adjacent to the male thread portion 33 is formed to have a smaller outer diameter than the male thread portion 33 .

[0014] In the inner diameter portion of the joint body 30, the inner diameter of the protruding portion 31 is formed smaller than the inner diameter of the male thread portion 33. The inner diameter of the protruding portion 31 is also formed smaller than the outer diameters of the first pipe 20 and the second pipe 21, and the inner diameter of the male thread portion 33 is formed so that the first pipe 20 and the second pipe 21 can be fitted thereto. In addition, annular rubber ring grooves 35 are formed near one outer end and near the other outer end of the inner diameter portion of the male thread portion 33. An annular joint edge portion 36 that protrudes radially inward is formed on the inner diameter portion of each end 34. The inner diameter of the joint edge portion 36 is formed smaller than the outer diameters of the first expanded pipe portion 22 of the first pipe 20 and the second expanded pipe portion 23 of the second pipe 21.

[0015] A metal loosening prevention ring 40 is attached to each joint groove 32. The loosening prevention ring 40 may be made of any metal, preferably stainless steel or copper, which is less susceptible to rust than the stainless steel and other metal materials that make up the first pipe 20, the second pipe 21, the joint body 30, and the nut 50, which will be described in detail later. An annular rubber ring 38 is attached to each rubber ring groove 35. The rubber ring 38 is made of any rubber material, such as a ternary fluororubber.

[0016] A nut 50, which is made of any metal material such as stainless steel, copper, or aluminum alloy, is attached to the joint body 30 to secure the first pipe 20 and the second pipe 21 to the joint body 30. With the first pipe 20 and the second pipe 21 inserted into the joint body 30, the nut 50 is fastened to the joint body 30 by threading a female thread portion 51 formed inside the nut 50 onto a male thread portion 33 of the joint body 30, thereby securing and connecting the first pipe 20 and the second pipe 21 to the joint body 30. An annular nut groove 52 capable of accommodating a loosening suppression ring 40 is formed at the end of the inner diameter portion of the nut 50 facing the joint body 30. The nut groove 52 is formed in a circular shape when viewed along the X direction. An annular nut edge 53 is formed at the end of the nut groove 52 closer to the protruding portion 31 of the joint body 30.

[0017] FIG. 2 is a side view of the loosening prevention ring 40 shown in FIG. 1 , viewed along the X direction. FIG. 3 is a perspective view of the loosening prevention ring 40 shown in FIG. 2 . The loosening prevention ring 40 will be described below with reference to FIGS. 2 and 3 . The loosening prevention ring 40 has an annular shape and includes an open portion 41, which is a portion of the circumferential portion that is interrupted, an annular portion 42 formed in a partial annular shape along the circumferential direction, a plate-shaped flange portion 43 extending radially outward from the annular portion 42, and a plate-shaped protruding portion 44 protruding radially outward from the flange portion 43. The annular portion 42 has an annular plate shape extending along the X direction and has notches 45 formed at equal angular intervals along the circumferential direction. The protruding portions 44 are formed at equal angular intervals along the circumferential direction. The loosening prevention ring 40 is formed by stamping a plate-shaped metal member made of any elastic metal material, such as stainless steel, and then bending the annular portion 42.

[0018] In the following description, the distance between the annular portion 42 and the tip of the protrusion 44 is referred to as the height H of the protrusion 44. Referring to FIG. 2, the height H of the protrusion 44a adjacent to the open portion 41 on the counterclockwise side is the smallest among the protrusions 44. The protrusions 44 are arranged in the order of 44a, 44b, 44c, 44d, 44e, 44f, 44g, and 44h, in a clockwise direction from the protrusion 44a, with the height H increasing in that order. Furthermore, the height of the protrusion 44i adjacent to the protrusion 44h on the clockwise side is the same height H as the protrusion 44a. Furthermore, the heights H of the protrusions 44 are arranged in the order of 44i, 44j, 44k, 44l, 44m, 44n, 44o, and 44p, in a clockwise direction from the protrusion 44i, with the height H increasing in that order. That is, the height H of each of the protrusions 44a, 44b, 44c, 44d, 44e, 44f, 44g, 44h, 44i, 44j, 44k, 44l, 44m, 44n, 44o, and 44p is different from the height of adjacent protrusions. The height H of each of the protrusions 44a, 44b, 44c, 44d, 44e, 44f, 44g, 44h, 44i, 44j, 44k, 44l, 44m, 44n, 44o, and 44p is greater than the radial length of the nut edge portion 53 of the nut 50 shown in FIG.

[0019] The loosening preventive ring 40 has an open portion 41 and is made of an elastic metal member, so that it can be bent to change its shape. The length of the open portion 41 is set to a length that allows the loosening preventive ring 40 to be deformed so that the joint groove portion 32 of the joint body 30 can be inserted into the open portion 41 and the loosening preventive ring 40 can be attached to the joint groove portion 32.

[0020] Next, a method for connecting the first pipe 20 and the second pipe 21 of the pipe joint structure 1 using the joint body 30 will be described. First, loosening prevention rings 40 are attached to the two joint grooves 32 of the joint body 30 shown in Fig. 1. Here, as shown in Fig. 2, the loosening prevention ring 40 is formed from an elastic metal member and has an open portion 41. Therefore, by inserting the joint groove 32 into the loosening prevention ring 40 while widening the open portion 41, the loosening prevention ring 40 can be placed in the joint groove 32.

[0021] Next, rubber rings 38 are placed in the two rubber ring grooves 35 of the joint body 30 shown in Figure 1. Next, the first pipe 20 is inserted into the nut 50, and the first expanded portion 22 is formed using a known pipe expanding tool. Also, the second pipe 21 is inserted into the nut 50, and the second expanded portion 23 is formed using a known pipe expanding tool.

[0022] 4 is a half-side cross-sectional view of the pipe fitting structure 1 with the nut 50 temporarily fastened to the fitting body 30. After the first expanded pipe portion 22 and the second expanded pipe portion 23 are formed, the first pipe 20 and the second pipe 21 are inserted into the fitting body 30. Next, the female thread portion 51 of the nut 50 on the first pipe 20 side is manually threaded onto the male thread portion 33 of the fitting body 30, and the female thread portion 51 of the nut 50 on the second pipe 21 side is manually threaded onto the male thread portion 33 of the fitting body 30. As a result, each nut 50 is attached to the fitting body 30 in a temporarily fastened state. The temporarily fastened position of each nut 50 at this time constitutes the first position.

[0023] FIG. 5 is an enlarged cross-sectional view of the second pipe 21, joint groove 32, loosening prevention ring 40, and nut groove 52 shown in FIG. 4. In the following description, FIGS. 5, 6, and 8 are enlarged cross-sectional views of the second pipe 21, joint groove 32, loosening prevention ring 40, and nut groove 52 on the side where the second pipe 21 is provided, but the first pipe 20, joint groove 32, loosening prevention ring 40, and nut groove 52 on the side where the first pipe 20 is provided have similar configurations. In the following description, the nut 50 and loosening prevention ring 40 on the side where the second pipe 21 is provided will be described in detail, but the nut 50 and loosening prevention ring 40 on the side where the first pipe 20 is provided also have the same configuration and operation. When the nut 50 is temporarily fastened to the fitting body 30, the nut edge 53 of the nut groove 52 of the nut 50 is separated from the protruding portion 31 of the fitting body 30, and the protruding portion 44 of the loosening prevention ring 40 is not pressed against the nut edge 53.

[0024] Furthermore, when the nut 50 is temporarily fastened to the joint body 30, the rubber rings 38, which are sealing materials, are not in close contact with the first expanded pipe portion 22 and the second expanded pipe portion 23, so that refrigerant, high-temperature or low-temperature gas, hot or cold water, etc. circulating in the first pipe 20 or the second pipe 21 leaks out from the gap between the first expanded pipe portion 22 and the joint body 30, and the gap between the second expanded pipe portion 23 and the joint body 30. This makes it possible to sense that the nut 50 is temporarily fastened.

[0025] Fig. 6 is a cross-sectional view of the pipe fitting structure 1 shown in Fig. 4 taken along line A-A'. Protrusions 44a, 44b, 44c, 44d, 44e, 44f, 44g, 44h, 44i, 44j, 44k, 44l, 44m, 44n, 44o, and 44p of the loosening preventive ring 40 are formed to overlap nut edge portion 53 of the nut 50 when viewed along the X direction. Furthermore, the heights H of the protrusions 44 increase in the order of protrusions 44a, 44b, 44c, 44d, 44e, 44f, 44g, and 44h, which are arranged clockwise from protrusion 44a. Furthermore, the heights H of the protrusions 44 increase in the order of protrusions 44i, 44j, 44k, 44l, 44m, 44n, 44o, and 44p, which are arranged clockwise from protrusion 44i.

[0026] Next, each nut 50 is further tightened onto the fitting body 30 using a tool such as a pipe wrench to final tightening. Figure 7 is an enlarged cross-sectional view of the second piping 21, fitting groove 32, loosening preventive ring 40, and nut groove 52 during the process of final tightening the nuts 50. As the nuts 50 are tightened onto the fitting body 30, the nut edge 53 of the nut groove 52 comes into contact with the protrusion 44 of the loosening preventive ring 40, pressing the protrusion 44 radially inward, and bending the flange 43 and protrusion 44 radially inward.

[0027] 8 is a half-side cross-sectional view of the pipe fitting structure 1 when the process of fully tightening the nuts 50 is completed. When each nut 50 is fully tightened with a tool, the nut groove 52 is positioned radially outward of the fitting groove 32 of the fitting body 30. At this time, each rubber ring 38 serving as a sealing material is pressed and crushed by the first expansion portion 22 and the second expansion portion 23, thereby sealing the gap between the first pipe 20 and the fitting body 30 and the gap between the second pipe 21 and the fitting body 30, preventing leakage of fluid flowing through the first pipe 20 and the second pipe 21. The fully tightened position of each nut 50 at this time constitutes the second position.

[0028] FIG. 9 is an enlarged cross-sectional view of the second pipe 21, the joint groove 32, the loosening prevention ring 40, and the nut groove 52 shown in FIG. 8 . When the nut 50 is tightened, the protrusion 44 of the loosening prevention ring 40 overcomes the nut edge 53 and is accommodated in the nut groove 52. At this time, the protrusion 44 is released from the pressure of the nut edge 53 and elastically extends to the bottom of the nut groove 52. That is, the protrusion 44 is fitted into the nut groove 52. Therefore, when the nut 50 is loosened after the final tightening process is completed, the protrusion 44 and the nut edge 53 come into contact, preventing the nut 50 from loosening. Therefore, to loosen the nut 50, a torque sufficient to cause the nut edge 53 to press and deform the protrusion 44 must be applied to the nut 50, increasing the torque required to loosen the nut 50. When a torque is applied to the nut 50 such that the protrusion 44 is pressed by the nut edge 53 and breaks, the nut 50 can be loosened.

[0029] After the nut 50 has been fully tightened, torque may be generated in a direction that loosens the nut 50 due to factors such as excessive vibration of the first pipe 20 and the second pipe 21, pressure changes in the fluid in the pipes, thermal contraction and thermal expansion, and the like that occur during operation of the piping equipment in which the pipe fitting structure 1 is installed. However, the torque in the direction that loosens the nut 50 that is generated due to such factors is not large enough to press and deform the protrusion 44 of the loosening preventive ring 40 with the nut edge portion 53, and therefore the nut 50 cannot be loosened. In other words, the loosening preventive ring 40 of the first embodiment improves the torque for loosening the nut 50, and therefore loosening of the nut 50 due to various factors that loosen the torque of the nut 50 that occur during operation of the piping equipment, such as those described above.

[0030] 6, in the first embodiment, the heights H of the protrusions 44a, 44b, 44c, 44d, 44e, 44f, 44g, and 44h are different from each other, and the heights H of the protrusions 44i, 44j, 44k, 44l, 44m, 44n, 44o, and 44p are different from each other. Therefore, even during the process of tightening the nut 50, any one of the protrusions 44a, 44b, 44c, 44d, 44e, 44f, 44g, and 44h and any one of the protrusions 44i, 44j, 44k, 44l, 44m, 44n, 44o, and 44p is accommodated and fitted in the nut groove 52. Therefore, even during the process of tightening the nut 50, the contact between the protrusion 44 and the nut edge 53 can provide the effect of preventing the nut 50 from loosening.

[0031] As described above, the pipe fitting structure according to the first embodiment includes the first pipe 20 or the second pipe 21, a fitting body 30 into which the end of the first pipe 20 or the second pipe 21 is inserted, a nut 50 that threads onto the fitting body 30 and fastens the first pipe 20 or the second pipe 21 to the fitting body 30, and a loosening prevention ring 40 that is provided in a fitting groove 32 formed on the outer diameter portion of the fitting body 30. The nut 50 has a nut groove 52 in which the loosening prevention ring 40 is accommodated in the inner diameter portion, and the loosening prevention ring 40 has an annular portion 42 extending circumferentially and a plurality of protrusions 44 that protrude radially outward. When the nut 50 fastens the first pipe 20 or the second pipe 21 to the fitting body 30, the protrusions 44 of the loosening prevention ring 40 are accommodated in the nut groove 52 of the nut 50, thereby reducing the possibility of the nut loosening during use of the pipe.

[0032] In addition, the nut groove portion 52 of the nut 50 has a nut edge portion 53 that protrudes radially inward at the end on the side that moves when the nut 50 is tightened, and when the nut 50 tightens the first pipe 20 or the second pipe 21 and the fitting body 30, at least some of the multiple protrusions 44 of the loosening prevention ring 40 engage with the nut edge portion 53, thereby increasing the torque required to loosen the nut and reducing the possibility of the nut loosening while the pipe is in use.

[0033] Furthermore, since the multiple protrusions 44 of the anti-loosening ring 40 have a different radially outward protrusion length relative to at least one other protrusion 44, the effect of preventing the nut from loosening can be obtained by contact between the protrusion and the edge of the nut even during the process of tightening the nut.

[0034] Furthermore, since the annular portion 42 of the loosening prevention ring 40 has a plurality of notches 45, the loosening prevention ring can be easily formed by punching.

[0035] In addition, the annular portion 42 of the anti-loosening ring 40 has a flange portion 43 that protrudes radially outward, and the protrusion 44 is provided on the flange portion 43, making it easy to form the protrusion by processing a plate-shaped metal member.

[0036] Furthermore, a method for assembling the pipe joint structure of this embodiment includes a first pipe 20 or a second pipe 21, a joint body 30 into which an end of the first pipe 20 or the second pipe 21 is inserted, a nut 50 that screws onto the joint body 30 and fastens the first pipe 20 or the second pipe 21 to the joint body 30, and a loosening prevention ring 40 that has an annular shape and is provided in a joint groove 32 formed on the outer diameter part of the joint body 30, the nut 50 having a nut groove 52 on its inner diameter part in which the loosening prevention ring 40 is accommodated, and the nut groove 52 has a radially extending groove 52 at the end on the side that advances when the nut is tightened. In a pipe fitting structure having a nut edge portion 53 protruding inward and a loosening prevention ring 40 having multiple protrusions 44 protruding radially outward, when the nut 50 is threaded onto the fitting body 30 and the nut 50 is in a first position, the protrusions 44 of the loosening prevention ring 40 are pressed by the nut edge portion 53 of the nut groove portion 52 of the nut 50, and when the nut 50 is further threaded and in a second position, the protrusions 44 of the loosening prevention ring 40 are accommodated in the nut groove portion 52, thereby reducing the possibility of the nut loosening during use of the pipe.

[0037] In addition, the loosening prevention ring 40 in this embodiment 1 is formed by punching out an elastic plate-shaped metal member such as stainless steel and bending the annular portion 42, but this is not limited to this, and it may also be formed, for example, by processing a metal member using laser processing or wire electric discharge processing and bending the annular portion.

[0038] Embodiment 2 Next, a pipe joint structure according to a second embodiment of the present invention will be described. In the following embodiments, the same reference numerals as those in Figures 1 to 9 of the first embodiment indicate the same or similar components, and detailed description thereof will be omitted. The pipe joint structure according to the second embodiment is different from the first embodiment in that the shape of the annular portion of the loosening prevention ring is changed. FIG. 10 is a side view of a loosening prevention ring 40a according to a second embodiment of the present invention, viewed from a direction along the central axis. FIG. 11 is a perspective view of the loosening prevention ring 40a shown in FIG. 10. The annular portion 42a of the loosening prevention ring 40a does not have a notch, and the annular portion 42a other than the open portion 41 is formed with a constant width along the X direction, which is the axial direction. The loosening prevention ring 40a also has a plate-shaped flange portion 43 extending radially outward from the annular portion 42, and multiple plate-shaped protrusions 44 protruding radially outward from the flange portion 43. The height of each protrusion 44 is different from the height of adjacent protrusions, similar to the height of each protrusion in the first embodiment. The other configurations are the same as those in the first embodiment.

[0039] In this way, in the pipe joint structure according to the second embodiment, the annular portion 42a of the loosening prevention ring 40 has a constant width along the axial direction, and therefore the strength of the loosening prevention ring 40 is improved.

[0040] Embodiment 3 Next, a pipe joint structure according to a third embodiment of the present invention will be described. In the third embodiment, the same reference numerals as those in Figures 10 and 11 of the second embodiment indicate the same or similar components, and detailed description thereof will be omitted. The pipe joint structure according to the third embodiment is different from the first embodiment in that the shape of the annular portion of the loosening prevention ring is changed. FIG. 12 is a side view of the loosening prevention ring 40b of the third embodiment, as viewed from the direction along the central axis. FIG. 13 is a perspective view of the loosening prevention ring 40b shown in FIG. 12. The annular portion 42a of the loosening prevention ring 40a does not have a notch, and the annular portion 42a other than the open portion 41 is formed with a constant width along the X direction, which is the axial direction. Furthermore, the loosening prevention ring 40b does not have a flange portion, but has multiple plate-shaped protrusions 44 that protrude directly radially outward from the annular portion 42. The height of each protrusion 44 is formed to be different from the height of adjacent protrusions, similar to the height of each protrusion in the first embodiment. The other configurations are the same as those in the first embodiment.

[0041] In this way, the protrusion 44 of the loosening restricting ring 40b according to the third embodiment is provided at the end of the annular portion 42a, which simplifies the formation of the protrusion 44.

[0042] In the pipe fitting structure of the present invention, loosening prevention ring 40 is used in embodiment 1, loosening prevention ring 40a is used in embodiment 2, and loosening prevention ring 40b is used in embodiment 3, but the shapes of the loosening prevention rings in embodiments 1 to 3 are merely examples, and loosening prevention rings having other suitable shapes may also be used.

[0043] Furthermore, although the pipe joint structure of the present invention has the joint body 30 that connects the first pipe 20 and the second pipe 21 in a straight line, the configuration of the joint body is not limited to this. For example, a curved joint body may be used to connect the second pipe in a direction perpendicular to the first pipe, or a joint body that connects three or more pipes may be used.

[0044] Furthermore, although the loosening prevention ring 40 of embodiment 1 of the present invention, the loosening prevention ring 40a of embodiment 2, and the loosening prevention ring 40b of embodiment 3 are formed from a metal material, the loosening prevention ring may also be formed from a resin material having sufficient elasticity and strength. [Explanation of symbols]

[0045] 20 first pipe, 21 second pipe, 30 fitting body (pipe fitting), 32 fitting groove portion, 40, 40a, 40b loosening prevention ring (loosening prevention member), 42 ring-shaped portion, 43 flange portion, 44, 44a, 44b, 44c, 44d, 44e, 44f, 44g, 44h, 44i, 44j, 44k, 44l, 44m, 44n, 44o, 44p protrusion portion, 50 nut (fastening member), 52 nut groove portion (accommodating portion), 53 nut edge portion (edge ​​portion).

Claims

1. Piping and a pipe joint into which the end of the pipe is inserted; a nut that is threaded onto the pipe joint and fastens the pipe and the pipe joint; a loosening suppression member provided in a joint groove formed in an outer diameter portion of the pipe joint; Equipped with The nut has an accommodation portion in an inner diameter portion in which the loosening suppression member is accommodated, The loosening inhibiting member has a ring-shaped portion extending in a circumferential direction and a plurality of protruding portions protruding radially outward, When the nut fastens the pipe and the pipe joint, the protruding portion of the loosening suppression member is accommodated in the accommodating portion of the nut.

2. The accommodating portion of the nut has an edge portion that protrudes radially inward at an end portion on a side that moves when the nut is tightened, The pipe joint structure according to claim 1 , wherein when the nut fastens the pipe and the pipe joint, at least some of the plurality of protrusions of the loosening inhibiting member engage with the edge portion.

3. The pipe joint structure according to claim 1 or 2, wherein the plurality of protrusions of the loosening inhibiting member have a radially outward protrusion length that is different from that of at least one other protrusion.

4. The pipe joint structure according to claim 1 or 2, wherein the annular portion of the loosening inhibiting member has a plurality of notches.

5. 3. The pipe joint structure according to claim 1, wherein the annular portion of the loosening inhibiting member has a flange portion that protrudes radially outward, and the protrusion is provided on the flange portion.

6. The pipe joint structure according to claim 1 or 2, wherein the annular portion of the loosening inhibiting member has a constant width along the axial direction.

7. The pipe joint structure according to claim 1 or 2, wherein the protrusion of the loosening suppression member is provided at an end of the annular portion.

8. Piping and a pipe joint into which the end of the pipe is inserted; a nut that is threaded onto the pipe joint and fastens the pipe and the pipe joint; a loosening suppression member having a ring-like shape and provided in a joint groove formed in an outer diameter portion of the pipe joint; Equipped with The nut has an accommodation portion in an inner diameter portion in which the loosening suppression member is accommodated, The accommodating portion has an edge portion that protrudes radially inward at an end portion on a side that moves when the nut is tightened, In the pipe joint structure, the loosening suppression member has a plurality of protrusions protruding radially outward, a step in which, when the nut is fastened to the pipe joint and the nut is in a first position, the protrusion of the loosening suppression member is pressed by the edge of the accommodation portion of the nut; and a step of receiving the protruding portion of the loosening inhibiting member in the receiving portion when the nut is further tightened to a second position.

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