Pipe joint

Abstract

To provide a pipe joint capable of restraining a pipe from slipping out of the pipe joint.SOLUTION: The pipe joint 100 includes a joint body 101, a retaining ring 104a disposed on an inner peripheral surface of the joint body 101 and having a bent piece inclined inward in an axial direction of the joint body 101, and a protrusion 211 disposed on an outer side in the axial direction with respect to the bent piece and having an inclined surface inclined inward in the axial direction toward an inner side in a radial direction.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] A known pipe joint has two retaining rings with an auxiliary spacer ring between them. With this pipe joint, after a pipe is inserted into the joint body and connected, the two retaining rings can prevent the connected pipe from slipping out (see, for example, Patent Document 1).

[0003] Also, some pipe joints are known that are provided with a single retaining ring and an auxiliary ring that prevents deformation of the retaining ring. With this pipe joint, when the connected pipe is pulled relative to the joint body, the auxiliary ring can prevent the retaining ring from deforming due to the tensile force. Therefore, the single retaining ring and the auxiliary ring can prevent the connected pipe from coming loose (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-068923 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-162786 Summary of the Invention [Problem to be solved by the invention]

[0005] However, with the pipe fitting of Patent Document 1, if the connected pipe is pulled excessively against the fitting body at the construction site, the retaining ring may be deformed by the excessive tensile force. The deformed retaining ring may be turned over in the pulling direction, causing the pipe to come out of the pipe fitting. Furthermore, the auxiliary spacer rings between the retaining rings are thin. Therefore, when the pipe is inserted into the fitting body, there is a possibility that the two retaining rings will pierce the same spot on the pipe. As a result, when the connected pipe is pulled against the fitting body, the two retaining rings will dig into the pipe, concentrating stress on the pipe and making it more likely to break at the punctured point.

[0006] Furthermore, with the auxiliary ring of Patent Document 2, it is difficult to prevent deformation of the retaining ring when the connected pipe is pulled excessively against the fitting body at the construction site, which can cause the retaining ring to deform and turn over due to excessive pulling force, making it easier for the pipe to come out of the pipe fitting.

[0007] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a pipe joint that can prevent a pipe from slipping out of the pipe joint. [Means for solving the problem]

[0008] A pipe fitting according to one aspect of the present invention comprises a fitting body, a retaining ring arranged on the inner surface of the fitting body and having a bent piece that inclines inward in the axial direction of the fitting body, and a convex portion arranged axially outward from the bent piece and having an inclined surface that inclines inward in the axial direction as it extends radially inward. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a pipe joint that can prevent a pipe from slipping out of the pipe joint. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a perspective view showing a pipe joint according to a first embodiment of the present invention, the perspective view including a partial cross section. [Figure 2] FIG. 2 is an exploded perspective view showing the component configuration of the pipe joint according to the first embodiment. [Figure 3] FIG. 2 is an enlarged cross-sectional view of part A in FIG. [Figure 4] FIG. 4 is an enlarged cross-sectional view of part B in FIG. 3. [Figure 5] 1 is a cross-sectional view showing a state in which an excessive tensile force is applied to a pipe connected to a pipe joint according to a first embodiment. FIG. [Figure 6] FIG. 10 is a cross-sectional view showing a pipe joint of a comparative example. [Figure 7] FIG. 10 is a cross-sectional view showing a state in which excessive tension is generated in a pipe connected to a pipe fitting of a comparative example. [Figure 8] FIG. 6 is a cross-sectional view showing a pipe joint according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, a pipe joint according to one embodiment of the present invention will be described with reference to the drawings. (First embodiment) 1 and 2, the pipe fitting 100 comprises a fitting body 101, a nut 102, a watertight portion 103, a fixing portion 104, and an inner core 105. The pipe fitting 100 according to the first embodiment is a component for connecting a plurality of pipes (tubes) P for water intake, hot water supply, or air conditioning equipment in a building. The pipe fitting 100 and the pipes P connected to this pipe fitting 100 form a piping structure. In the following description, the direction along the central axis of the joint body 101 will be referred to as the axial direction, and the direction intersecting the central axis in a plan view of the joint body 101 from the axial direction will be referred to as the radial direction. Furthermore, the direction circumferentially around the central axis in the plan view will be referred to as the circumferential direction. Furthermore, the end face side of the joint body 101 will be referred to as the outer side in the axial direction, and the side opposite the end face will be referred to as the inner side in the axial direction.

[0012] The joint body 101 is formed in a tubular (cylindrical) shape. A step 113 is formed on the inner peripheral surface of the joint body 101. The step 113 protrudes radially inward from the inner peripheral surface of the joint body 101. The step 113 is provided around the entire circumference in the circumferential direction. On the inner peripheral surface of the joint body 101, the inner diameter gradually decreases (in steps) from the outside to the inside in the axial direction. An incore 105 formed separately from the joint body 101 abuts against the step 113.

[0013] The inner core 105 is disposed along the inner peripheral surface of the joint body 101. The inner core 105 is formed, for example, by injection molding of a synthetic resin material, or by cutting, casting, or forging of a metal material. The synthetic resin material can be selected arbitrarily based on the quality design according to the application, such as cross-linked polyethylene, polybutene, polyvinyl chloride (PVC), polysulfone resin (PSU), polycarbonate resin (PC), polyamide resin (PA), polyacetal resin (POM), polyphenylsulfone resin (PPSU), polyphenylene sulfide resin (PPS), glass fiber reinforced PPS, polyvinylidene fluoride (PVDF), etc. Other processing methods such as cutting and fusion may also be used. The metal material can be selected arbitrarily based on the quality design according to the application, such as stainless steel, low alloy steel, carbon steel, low temperature carbon steel, low temperature alloy steel, brass, gunmetal, aluminum alloy, magnesium alloy, etc. Hereinafter, the portion of the joint body 101 from the end face of the joint body 101 to the step 113 will be referred to as the open end of the joint body 101.

[0014] An outer flange portion 101a and a male thread portion 101b are formed on the outer peripheral surface of each of both axial ends of the joint body 101. The outer flange portion 101a protrudes radially outward from the joint body 101. The outer flange portion 101a extends around the entire outer circumferential surface of the joint body 101. The male thread portion 101b is formed on the outer peripheral surface of the joint body 101 at a portion located axially outward of the outer flange portion 101a (that is, closer to the end face of the joint body 101).

[0015] The nut 102 is disposed at the end of the joint body 101. The nut 102 is cylindrical with an outer diameter that decreases stepwise in the axial direction. The nut 102 includes a first tube 102a having a female thread 102h (see FIG. 3) formed on its inner circumferential surface, and a second tube 102b located outward in the axial direction from the first tube 102a. The first tube 102a has a female thread 102h that is threaded onto the male thread portion 101b. Thus, the nut 102 is provided at the end of the joint body 101. A step 102d is provided on the inner circumference of the nut 102 at a portion that corresponds to the boundary between the first tube 102a and the second tube 102b. The step 102d extends around the entire circumference. The step 102d contacts or is close to the end face of the joint body 101 that faces outward in the axial direction.

[0016] The second tube 102b has a smaller diameter than the first tube 102a. The second tube 102b extends axially outward from the first tube 102a. The second tube 102b has a third tube portion 102e and a fourth tube portion 102f. The third tube portion 102e is provided at the axially outer end of the first tube 102a. The third tube portion 102e has an outer diameter that gradually decreases as it extends axially outward from the end of the first tube 102a. The fourth tube portion 102f is provided at the axially outer end of the third tube portion 102e. The fourth tube portion 102f has an outer diameter smaller than that of the first tube 102a. The inner circumferential surfaces 102g of the third tube portion 102e and the fourth tube portion 102f are formed so that the pipe P can be inserted therein and can stably support the pipe P. The nut 102 is formed by, for example, injection molding of a synthetic resin material, or cutting, casting, or forging of a metal material. The nut 102 also has a first protrusion 212 (see FIG. 4). The first protrusion 212 will be described in detail later.

[0017] In the pipe fitting 100, an accommodating recess 106 for accommodating the watertight portion 103 and the fixing portion 104 is formed between the fitting body 101 and the nut 102. The accommodating recess 106 is formed between the step 102d and the end face of the fitting body 101 that faces outward in the axial direction. The accommodating recess 106 extends around the entire circumferential direction.

[0018] The joint body 101 is formed, for example, by injection molding of a synthetic resin material, or by cutting, casting, or forging of a metal material. The nut 102 is formed, for example, by injection molding of a synthetic resin material, or by cutting, casting, or forging of a metal material. The synthetic resin material can be selected arbitrarily based on quality design depending on the application, such as cross-linked polyethylene, polybutene, polyvinyl chloride (PVC), polysulfone resin (PSU), polycarbonate resin (PC), polyamide resin (PA), polyacetal resin (POM), polyphenylsulfone resin (PPSU), polyphenylene sulfide resin (PPS), glass fiber reinforced PPS, polyvinylidene fluoride (PVDF), etc. Other processing methods such as cutting and fusion may also be used. The metal material can be arbitrarily selected from stainless steel, low alloy steel, carbon steel, low temperature carbon steel, low temperature alloy steel, brass, gunmetal, aluminum alloy, magnesium alloy, etc. based on quality design according to the intended use.

[0019] A watertight portion 103 and a fixing portion 104 are provided at the axial end of the fitting body 101. The watertight portion 103 is composed of a gasket 103a and a base member 103b. The fixing portion 104 is composed of a retaining ring 104a and an auxiliary spacer ring 104b. The retaining ring 104a includes a first retaining ring 104c and a second retaining ring 104d. The first retaining ring 104c is disposed on the insertion side of the pipe P (i.e., the outer side in the axial direction). The second retaining ring 104d is disposed on the opposite side of the first retaining ring 104c from the insertion side of the pipe P (i.e., the inner side in the axial direction).

[0020] At the axial end of the fitting body 101, in this order toward the end face of the fitting body 101, there are provided a packing 103a, a base member 103b, a second retaining ring 104d, an auxiliary spacer ring 104b, and a first retaining ring 104c. That is, the fixing portion 104 is located closer to the end face than the watertight portion 103. The watertight portion 103 (i.e., the packing 103a and the base member 103b) prevents the contents of the pipe P from leaking out of the pipe fitting 100. The pipe P inserted into the pipe fitting 100 is fixed to the pipe fitting 100 by the fixing portion 104 (i.e., the first retaining ring 104c, the auxiliary spacer ring 104b, and the second retaining ring 104d).

[0021] The packing 103a is disposed on the inner peripheral surface of the joint body 101. In the illustrated example, one packing 103a is provided, but multiple packings 103a may be provided spaced apart in the axial direction. The packing 103a is annular with a circular cross section. The packing 103a extends around the entire circumference in the circumferential direction. In the illustrated example, an O-ring is used as the packing 103a. The packing 103a can be made of rubber materials such as ethylene propylene diene rubber (EPDM), fluororubber (FKM), vinyl methyl silicone rubber (VMQ), acrylonitrile butadiene rubber (NBR), styrene butadiene rubber (SBR), and chloroprene rubber (CR).

[0022] The base member 103b is disposed on the inner circumferential surface of the joint body 101. The base member 103b is disposed between the packing 103a and the second retaining ring 104d. The base member 103b prevents contact between the packing 103a and the second retaining ring 104d. The base member 103b is formed in an annular shape. The base member 103b extends over the entire circumferential direction. The base member 103b is fitted into the open end of the joint body 101. The base member 103b contacts a first step, which is a step provided on the inner circumferential surface of the joint body 101. The base member 103b is hooked onto the first step of the joint body 101 from the outside in the axial direction. The inner diameter of the base member 103b is larger than the inner diameter of the packing 103a.

[0023] The base member 103b is formed by, for example, injection molding of a synthetic resin material, or cutting, casting, or forging of a metal material. The synthetic resin material can be selected arbitrarily based on quality design depending on the application, such as cross-linked polyethylene, polybutene, polyvinyl chloride (PVC), polysulfone resin (PSU), polycarbonate resin (PC), polyamide resin (PA), polyacetal resin (POM), polyphenylsulfone resin (PPSU), polyphenylene sulfide resin (PPS), glass fiber reinforced PPS, polyvinylidene fluoride (PVDF), etc. Other processing methods such as cutting and fusion may also be used. The metal material can be arbitrarily selected from stainless steel, low alloy steel, carbon steel, low temperature carbon steel, low temperature alloy steel, brass, gunmetal, aluminum alloy, magnesium alloy, etc. based on quality design according to the intended use.

[0024] The first retaining ring 104c, the auxiliary spacer ring 104b, and the second retaining ring 104d are disposed on the inner circumferential surface of the joint body 101. The first retaining ring 104c, the auxiliary spacer ring 104b, and the second retaining ring 104d are formed in annular shapes. Specifically, the first retaining ring 104c, the auxiliary spacer ring 104b, and the second retaining ring 104d are disposed axially outward from the base member 103b. The first retaining ring 104c, the auxiliary spacer ring 104b, and the second retaining ring 104d are disposed in the installation recess 106 of the joint body 101.

[0025] The installation recess 106 is located axially outward of the first step. The first retaining ring 104c, the auxiliary spacer ring 104b, and the second retaining ring 104d are arranged in the installation recess 106 with some axial play. The first retaining ring 104c, the auxiliary spacer ring 104b, and the second retaining ring 104d are arranged in this order from the outside to the inside in the axial direction. The auxiliary spacer ring 104b is arranged in the installation recess 106, sandwiched axially between the first retaining ring 104c and the second retaining ring 104d.

[0026] As shown in Figures 3 and 4, the retaining ring 104a includes a first retaining ring 104c and a second retaining ring 104d. The first retaining ring 104c has a first ring body 202 and a first bent piece 203. The first ring body 202 is formed in an annular shape. An outer periphery 202a of the first ring body 202 extends circumferentially along the inner periphery of the installation recess 106 (the inner periphery of the joint body 101). For example, a plurality of first bent pieces 203 are integrally formed on an inner periphery 202b of the first ring body 202.

[0027] The multiple first bent pieces 203 are provided continuously around the entire circumferential direction along the inner circumference 202b of the first ring body 202. The multiple first bent pieces 203 are bent at an inclination angle θ1 so as to incline axially inward as they move radially inward from the inner circumference 202b of the first ring body 202. The multiple first bent pieces 203 have first tips 203a. Hereinafter, the multiple first bent pieces 203 may be simply referred to as "first bent pieces 203."

[0028] The second retaining ring 104d is formed in the same manner as the first retaining ring 104c. That is, the second retaining ring 104d has a second ring body 204 and a second bent piece (bent piece of the second retaining ring) 205. The second ring body 204 is formed in an annular shape. The outer periphery 204a of the second ring body 204 extends circumferentially along the inner circumferential surface of the installation recess 106 over the entire circumference. A plurality of second bent pieces 205 are integrally formed on the inner periphery 204b of the second ring body 204.

[0029] The multiple second bent pieces 205 are provided continuously around the entire circumferential direction along the inner circumference 204b of the second ring body 204. The multiple second bent pieces 205 are bent at an inclination angle θ1 so as to incline axially inward as they move radially inward from the inner circumference 204b of the second ring body 204. The multiple second bent pieces 205 have second tips 205a. Hereinafter, the multiple second bent pieces 205 may be simply referred to as "second bent pieces 205."

[0030] In this way, the first retaining ring 104c has the first bent piece 203, and the second retaining ring 104d has the second bent piece 205. Therefore, the first bent piece 203 and the second bent piece 205 form the bent piece 201 of the retaining ring 104a. In other words, the retaining ring 104a has the bent piece 201. The bent piece 201 includes the first bent piece 203 and the second bent piece 205.

[0031] The first bent piece 203 and the second bent piece 205 are spaced apart in the axial direction by an auxiliary spacer ring 104b. A first tip 203a of the first bent piece 203 and a second tip 205a of the second bent piece 205 bite into the outer periphery of the pipe P. Specifically, when the pipe P is inserted into the fitting body 101 and the nut 102, the female thread 102h of the nut 102 is threaded onto the male thread portion 101b. In other words, the nut 102 is threaded onto the fitting body 101. Therefore, the first tip 203a of the first bent piece 203 and the second tip 205a of the second bent piece 205 are maintained in a state of biting into the outer periphery of the pipe P. In this state, the pipe P inserted into the pipe fitting 100 is connected (fixed) to the pipe fitting 100 by the fixing portion 104. That is, the first bent piece 203 and the second bent piece 205 serve to prevent the pipe P from slipping out of the pipe joint 100.

[0032] Here, in the pipe fitting 100, there tends to be a trade-off between the pull-out strength and pull-out fatigue strength (durability) of the pipe P and the insertion force of the pipe P. For example, as the pull-out strength decreases, the insertability of the pipe P improves. Also, as the pull-out fatigue strength decreases, the insertability of the pipe P improves. Furthermore, as the insertion force increases, the insertability of the pipe P decreases. Therefore, it is preferable to select the materials of the first retaining ring 104c and the second retaining ring 104d as follows.

[0033] That is, when inserting a pipe P into a pipe fitting 100 equipped with the first retaining ring 104c and the second retaining ring 104d, it is preferable to suppress the insertion force of the pipe P. For this reason, the material for the first retaining ring 104c and the second retaining ring 104d is preferably SUS with a hardness of 430 HV or less. In addition, in order to maintain the pull-out strength and pull-out fatigue strength of the first retaining ring 104c and the second retaining ring 104d, a yield strength of 470 N / mm 2 Over 780N / mm 2 The above SUS is desirable.

[0034] Specifically, the first retaining ring 104c and the second retaining ring 104d are preferably made of, for example, SUS301 and SUS304, as shown in Table 1. SUS301 and SUS304 have hardness of 430 HV or less and yield strength of 470 N / mm 2 and tensile strength 780N / mm 2 The above conditions are met.

[0035] [Table 1]

[0036] Here, the pipe fitting 100 has a convex portion 211 in addition to the bent piece 201 (i.e., the first bent piece 203 and the second bent piece 205) to prevent the pipe P from slipping out of the pipe fitting 100. The convex portion 211 includes a first convex portion 212 corresponding to the first bent piece 203 and a second convex portion 214 corresponding to the second bent piece 205. Note that, in the first embodiment, an example will be described in which the convex portion 211 includes the first convex portion 212 and the second convex portion 214, but the convex portion 211 may be one of the first convex portion 212 and the second convex portion 214.

[0037] The first protrusion 212 is provided on the nut 102. The nut 102 is provided on the inner circumference of a step 102d of the nut 102. The step 102d is disposed axially outwardly with a gap from the first retaining ring 104c. The first protrusion 212 extends annularly around the entire circumferential direction along the inner circumference of the step 102d. The first protrusion 212 is disposed axially outwardly with a gap from the first bent piece 203 (i.e., the first retaining ring 104c).

[0038] The first protrusion 212 protrudes from the inner periphery of the step 102d toward the first bent piece 203 without contacting the pipe P. The first protrusion 212 has a first inclined surface (the inclined surface of the first protrusion 212) 212a. The first inclined surface 212a is provided on the inside in the axial direction of the first protrusion 212 (i.e., on the side of the first bent piece 203). The first inclined surface 212a is inclined inward in the axial direction at an inclination angle θ2 as it extends radially inward. The inclination angle θ2 of the first inclined surface 212a is smaller than the inclination angle θ1 of the first bent piece 203. The reason why the inclination angle θ2 of the first inclined surface 212a is smaller than the inclination angle θ1 of the first bent piece 203 will be explained in detail later. However, the inclination angle θ2 may be equal to or larger than the inclination angle θ1.

[0039] The second protrusion 214 is provided on the auxiliary spacer ring 104b. That is, the auxiliary spacer ring 104b has a ring body 213 and the second protrusion 214. The auxiliary spacer ring 104b is formed by, for example, injection molding of a synthetic resin material, or cutting, casting, or forging of a metal material. The ring body 213 is formed in an annular shape. The ring body 213 is disposed between the first ring body 202 and the second ring body 204 and sandwiched in the axial direction. The ring body 213 has a thickness of 0.5 mm or more and 3 mm or less. The reason for setting the thickness of the ring body 213 to 0.5 mm or more and 3 mm or less will be explained in detail later. However, the thickness of the ring body 213 may be less than 0.5 mm or may exceed 3 mm.

[0040] The outer periphery 213a of the ring body 213 extends circumferentially along the inner circumferential surface of the installation recess 106 over the entire circumference. A second protrusion 214 is provided on the inner periphery 213b of the ring body 213. That is, the second protrusion 214 is provided on the auxiliary spacer ring 104b. The second protrusion 214 is disposed between the first retaining ring 104c and the second retaining ring 104d. That is, the second protrusion 214 is disposed on the outer side in the axial direction relative to the second bent piece 205. The second protrusion 214 protrudes from the inner periphery 213b of the ring body 213 toward the second bent piece 205 without contacting the pipe P. The second protrusion 214 has a first inclined surface (the inclined surface of the second protrusion 214) 214a and a second inclined surface 214b.

[0041] The first inclined surface 214a is provided on the inner side in the axial direction (i.e., on the side of the second bent piece 205) of the second convex portion 214. The first inclined surface 214a is inclined inward in the axial direction at an inclination angle θ2 as it moves radially inward. That is, the first inclined surface 214a is inclined at the same inclination angle θ2 as the first inclined surface 212a of the first convex portion 212. The reason why the first inclined surface 212a of the first convex portion 212 and the first inclined surface 214a of the second convex portion 214 have the same inclination angle θ2 will be explained in detail later. The first inclined surface 212a and the first inclined surface 214a may have different inclination angles. Furthermore, the inclination angle θ2 of the first inclined surface 214a is smaller than the inclination angle θ1 of the second bent piece 205. The reason why the inclination angle θ2 of the first inclined surface 214a is smaller than the inclination angle θ1 of the first bent piece 203 will be explained in detail later. However, the inclination angle θ2 may be equal to or larger than the inclination angle θ1.

[0042] The second inclined surface 214b is provided on the outer side in the axial direction of the second protrusion 214 (i.e., on the side of the first bent piece 203). The second inclined surface 214b is inclined inward in the axial direction of the joint body 101 as it moves radially inward. The second inclined surface 214b is inclined at an inclination angle θ3 with respect to the first bent piece 203. The inclination angle θ3 is preferably 10° or more and 30° or less. The reason for setting the inclination angle θ3 to 10° or more and 30° or less will be explained with reference to FIG. 4 and Table 2. However, the inclination angle θ3 may be less than 10° or may exceed 30°.

[0043] [Table 2]

[0044] 4 and Table 2, when the inclination angle θ3 of the second inclined surface 214b is 0°, the average insertion force when inserting the pipe P into the pipe fitting 100 is 180 N. When the inclination angle θ3 of the second inclined surface 214b is 10°, the average insertion force when inserting the pipe P into the pipe fitting 100 is 165 N. Therefore, when the inclination angle θ3 of the second inclined surface 214b is 10°, the reduction rate of the insertion force for the pipe P can be increased by 8% compared to when the inclination angle θ3 is 0°.

[0045] Furthermore, when the inclination angle θ3 of the second inclined surface 214b is 30°, the average insertion force when inserting the pipe P into the pipe fitting 100 is 155 N. Therefore, when the inclination angle θ3 of the second inclined surface 214b is 30°, the reduction rate of the insertion force for the pipe P can be increased by 13% compared to when the inclination angle θ3 is 0°. Therefore, when the inclination angle θ3 of the second inclined surface 214b is 30°, the insertion force for the pipe P can be reduced by 5% compared to when the inclination angle θ3 is 10°.

[0046] On the other hand, when the inclination angle θ3 of the second inclined surface 214b is 40°, the average insertion force when inserting the pipe P into the pipe fitting 100 is 154 N. Therefore, when the inclination angle θ3 of the second inclined surface 214b is 40°, the insertion force for the pipe P is reduced by 14% compared to when the inclination angle θ3 is 0°. For this reason, when the inclination angle θ3 of the second inclined surface 214b is 40°, the insertion force for the pipe P can be reduced by only 1% compared to when the inclination angle θ3 is 30°. Therefore, it is preferable that the inclination angle θ3 be greater than or equal to 10° and less than or equal to 30°.

[0047] Next, a case where excessive tension occurs in the pipe P connected to the pipe fitting at a construction site will be described for the pipe fitting 100 of the first embodiment and the pipe fitting 400 of the comparative example. First, a case where an excessive tensile force F is generated in a pipe P connected to the pipe fitting 100 of the first embodiment will be described with reference to FIGS.

[0048] 3 and 4, at the construction site, with the pipe P inserted into the pipe fitting 100, the nut 102 is screwed onto the fitting body 101. The first bent piece 203 of the first retaining ring 104c and the second bent piece 205 of the second retaining ring 104d are kept inclined axially inward. The first tip 203a of the first bent piece 203 and the second tip 205a of the second bent piece 205 bite into the outer periphery of the pipe P.

[0049] In this state, for example, it is conceivable that an excessive tensile force F may be generated on the pipe P at the construction site. When an excessive tensile force F is generated on the pipe P, the pipe P moves outward in the axial direction as shown by arrow A. As the pipe P moves as shown by arrow A, the fixing part 104 moves together with the pipe P as shown by arrow A.

[0050] 5, when the fixing portion 104 moves in the direction of arrow A, the first retaining ring 104c comes into contact with the step 102d of the nut 102. In this state, the first bent piece 203 deforms in the direction of arrow A and comes into contact with the first inclined surface 212a of the first convex portion 212. In addition, the second bent piece 205 deforms in the direction of arrow A and comes into contact with the first inclined surface 214a of the second convex portion 214.

[0051] Therefore, the first inclined surface 212a and the first inclined surface 214a can prevent the orientation of the first bent piece 203 and the second bent piece 205 from being turned over from the inside in the axial direction toward the direction of arrow A. That is, the first bent piece 203 and the second bent piece 205 can be kept in a state inclined toward the inside in the axial direction (i.e., a state inclined in the opposite direction to the removal direction of the pipe P). Furthermore, the first inclined surface 212a and the first inclined surface 214a have the same inclination angle θ2. Therefore, the first tip 203a of the first bent piece 203 and the second tip 205a of the second bent piece 205 can be properly inserted into the pipe P. This makes it possible to prevent the pipe P from coming loose (specifically, from slipping out completely) from the pipe fitting 100. Hereinafter, the pipe P slipping out completely may be referred to as "the pipe P slipping out completely."

[0052] For example, test sample 1 of the pipe fitting 100 of the first embodiment was prepared by connecting a 250 mm pipe to a Φ20 pipe fitting (metal male adapter) with two retaining ring structures. Test sample 2 was prepared by connecting a 250 mm pipe to a Φ20 pipe fitting (metal male adapter) with a single retaining ring structure. Test samples 1 and 2 were subjected to tension measurement at 20 mm / min using a Tensilon universal testing machine. The tensile strength of test sample 1 was 4.3 kN, and the tensile strength of test sample 2 was 3.8 kN. The tensile strength of 4.3 kN of the pipe fitting 100 of the first embodiment is higher than the tensile strength of 3.8 kN of a pipe fitting with a single retaining ring structure.

[0053] Next, a case where an excessive tensile force F is generated in a pipe P connected to the pipe fitting 400 of the comparative example will be described with reference to Figures 6 and 7. Note that in the pipe fitting 400, parts that are the same as or similar to those in the pipe fitting 100 of the embodiment are given the same reference numerals and omitted.

[0054] As shown in Figure 6, the pipe fitting 400 of the comparative example does not have a first protrusion 212 on the nut 402. Furthermore, the auxiliary spacer ring 404b does not have a second protrusion 214. With this pipe fitting 400, at the construction site, with a pipe P inserted into the pipe fitting 400, the nut 402 is screwed onto the fitting body 101. The first bent piece 203 of the first retaining ring 104c and the second bent piece 205 of the second retaining ring 104d are kept inclined axially inward. The first tip 203a of the first bent piece 203 and the second tip 205a of the second bent piece 205 bite into the outer periphery of the pipe P.

[0055] In this state, for example, it is conceivable that excessive tensile force F may be generated on the pipe P at the construction site. When excessive tensile force F is generated on the pipe P, the pipe P moves outward in the axial direction as shown by arrow A. As the pipe P moves as shown by arrow A, the fixing part 404 moves together with the pipe P as shown by arrow A.

[0056] As shown in FIG. 7, when the fixing portion 104 moves as indicated by arrow A, the first ring body 202 of the first retaining ring 104c comes into contact with the step 402d of the nut 402. In this state, the first bent piece 203 deforms in the direction of arrow A. As a result, the orientation of the first bent piece 203 flips from the inside in the axial direction to the direction of arrow A. The second bent piece 205 also deforms in the direction of arrow A. As a result, the orientation of the second bent piece 205 flips from the inside in the axial direction to the direction of arrow A. As the first bent piece 203 and the second bent piece 205 flip over, it is thought that the pipe P may slip out.

[0057] For example, test sample 3 of comparative pipe fitting 400 was prepared by connecting a 250 mm pipe to a Φ20 pipe fitting (metal male adapter) with two retaining rings. Test sample 3 was stretched at 20 mm / min using a Tensilon universal testing machine. The tensile strength of test sample 3 was 4.0 kN. In other words, the tensile strength of comparative pipe fitting 400 is lower than the 4.3 kN tensile strength of the pipe fitting 100 of the first embodiment.

[0058] In the pipe fitting 100 according to the first embodiment described above, as shown in Figures 3 to 5, the convex portion 211 is disposed on the outer side in the axial direction relative to the bent piece 201. Furthermore, the inclined surface of the convex portion 211 inclines inward in the axial direction as it extends radially inward. Therefore, the convex portion 211 can, for example, keep the bent piece 201 of the retaining ring 104a inclined in the opposite direction to the removal direction of the pipe P. Therefore, for example, if excessive tensile force F is applied to the pipe P at a construction site, the convex portion 211 can prevent the bent piece 201 of the retaining ring 104a from deforming in the removal direction of the pipe P and flipping over. This prevents the pipe P from coming out of the pipe fitting 100, or from slipping out completely.

[0059] Furthermore, the retaining ring 104a includes two rings, a first retaining ring 104c and a second retaining ring 104d. Therefore, when excessive tensile force F is applied to the pipe P, the two bent pieces, the first bent piece 203 and the second bent piece 205, of each ring can be caused to bite into the pipe P. This ensures an appropriate limit tensile strength for the pipe P, and prevents the pipe P from slipping out.

[0060] Furthermore, two convex portions, a first convex portion 212 and a second convex portion 214, are provided as the convex portion 211. The first convex portion 212 is provided on the nut 102, and the second convex portion 214 is provided on the auxiliary spacer ring 104b. The nut 102 and the auxiliary spacer ring 104b are existing parts that are provided on ordinary pipe fittings. This makes it possible to provide the first convex portion 212 and the second convex portion 214 without increasing the number of parts of the pipe fitting 100.

[0061] Here, the reason why the first inclined surface 212a of the first convex portion 212 and the first inclined surface 214a of the second convex portion 214 are set to the same inclination angle θ2 will be explained. That is, if the inclination angles of the first inclined surface 212a and the first inclined surface 214a are different, the state in which the first bent piece 203 and the second bent piece 205 bite into the pipe P will differ when excessive tensile force F is generated on the pipe P. Furthermore, if the inclination angles of the first inclined surface 212a and the first inclined surface 214a are different, the amount of penetration into the pipe P (depth of penetration into the pipe P) will differ. For this reason, when excessive tensile force F is generated on the pipe P, for example, one of the first bent piece 203 and the second bent piece 205 will not be able to sufficiently bite into the pipe P, and the ultimate tensile strength of the pipe P will decrease.

[0062] Therefore, the first inclined surface 212a and the first inclined surface 214a are set to the same inclination angle θ2. Therefore, when excessive tensile force F is generated in the pipe P, the two bent pieces, the first bent piece 203 and the second bent piece 205, can be maintained at the same inclination angle by the first inclined surface 212a and the first inclined surface 214a. That is, the first bent piece 203 and the second bent piece 205 can be caused to bite into the pipe P in the same state. Furthermore, the amount of biting into the pipe P by the first bent piece 203 and the second bent piece 205 can be ensured to be the same. This allows the first bent piece 203 and the second bent piece 205 to be caused to bite into the pipe P in the same state, and the ultimate tensile strength of the pipe P can be appropriately ensured.

[0063] Next, the reason why the inclination angle θ2 of the first inclined surface 212a is made smaller than the inclination angle θ1 of the first bent piece 203, and further why the inclination angle θ2 of the first inclined surface 214a is made smaller than the inclination angle θ1 of the first bent piece 203 will be explained. That is, the inclination angle θ2 of the first inclined surface 212a is set smaller than the inclination angle θ1 of the first bent piece 203. Therefore, when excessive tensile force F is applied to the pipe P, the amount by which the first bent piece 203 bites into the pipe P can be made larger than the amount by which the pipe P is inserted. Furthermore, the inclination angle θ2 of the first inclined surface 214a is set smaller than the inclination angle θ1 of the second bent piece 205. Therefore, when excessive tensile force F is applied to the pipe P, the amount by which the second bent piece 205 bites into the pipe P can be made larger than the amount by which the pipe P is inserted. This allows the first bent piece 203 and the second bent piece 205 to appropriately ensure the ultimate tensile strength for the pipe P.

[0064] Next, the reason why the thickness of the ring body 213 of the auxiliary spacer ring 104b is set to 0.5 mm or more and 3 mm or less will be explained. That is, when the thickness of the ring body 213 is less than 0.5 mm, the first retaining ring 104c and the second retaining ring 104d are arranged close to each other in the axial direction. Therefore, the first bent piece 203 of the first retaining ring 104c and the second bent piece 205 of the second retaining ring 104d tend to bite into the same part of the pipe P in the axial direction. Therefore, when excessive tensile force F is applied to the pipe P, the pipe P tends to break at the part where the first bent piece 203 and the second bent piece 205 bite into each other.

[0065] Furthermore, if the thickness of the ring body 213 exceeds 3 mm, the distance between the first retaining ring 104c and the second retaining ring 104d will be long. Therefore, when inserting the pipe P into the pipe fitting 100, the insertion distance of the pipe P will be long. This may result in the pipe P not being fully inserted into the pipe fitting 100.

[0066] Therefore, the thickness of the ring body 213 is set to 0.5 mm or more and 3 mm or less. This allows the first retaining ring 104c and the second retaining ring 104d to be positioned with an appropriate distance between them in the axial direction. This allows the first bent piece 203 of the first retaining ring 104c and the second bent piece 205 of the second retaining ring 104d to be spaced apart in the axial direction and to be inserted into the pipe P. Therefore, even if excessive tensile force F is applied to the pipe P, it is possible to prevent the pipe P from breaking at the point where the first bent piece 203 or the second bent piece 205 is inserted into it.

[0067] Furthermore, by arranging the first retaining ring 104c and the second retaining ring 104d at an appropriate distance in the axial direction, it is possible to appropriately reduce the insertion distance of the pipe P. This makes it possible to prevent the pipe P from being insufficiently inserted into the pipe fitting 100 when inserting the pipe P into the pipe fitting 100.

[0068] Next, a pipe fitting 300 of a second embodiment will be described with reference to Fig. 8. In the second embodiment, the same or similar members as those of the pipe fitting 100 of the first embodiment will be given the same reference numerals and detailed description thereof will be omitted. (Second embodiment)

[0069] As shown in Figure 8, the pipe fitting 300 has the nut 102 of the first embodiment replaced with a nut 302, and further has the fixing portion 104 of the first embodiment replaced with a fixing portion 304. The other configuration of the pipe fitting 300 is similar to that of the pipe fitting 100 of the first embodiment. The nut 302 is the nut 102 of the first embodiment from which the first protrusion 212 has been removed. The fixing portion 304 further comprises a ring 305 in addition to the fixing portion 104 of the first embodiment. The other configuration of the fixing portion 304 is similar to that of the fixing portion 104 of the first embodiment.

[0070] The ring 305 is disposed in the installation recess 106 between the nut 302 and the first retaining ring 104c. The ring 305 has a ring body 313 and a first protrusion 314. The ring 305 is formed, for example, by injection molding of a synthetic resin material, or by cutting, casting, or forging of a metal material. The ring body 313 is formed in an annular shape. The ring body 313 is arranged axially between the step 302a of the nut 302 and the first retaining ring 104c. The ring body 313 is arranged in contact with the first ring body 202 of the first retaining ring 104c.

[0071] The outer periphery 313a of the ring body 313 extends circumferentially along the inner circumferential surface of the installation recess 106 over the entire circumference. A first protrusion 314 is provided on the inner periphery 313b of the ring body 313. That is, the first protrusion 314 is provided on the ring 305. The first protrusion 314 is disposed axially outward from the first bent piece 203 of the first retaining ring 104c. The first protrusion 314 protrudes from the inner periphery 313b of the ring body 313 toward the first bent piece 203 without coming into contact with the pipe P.

[0072] Additionally, the auxiliary spacer ring 104b is provided with a second convex portion 214. Therefore, similar to the first embodiment, the convex portion 311 is configured with the first convex portion 314 and the second convex portion 214. In other words, the convex portion 311 includes the first convex portion 314 and the second convex portion 214. Note that, in the second embodiment, an example will be described in which the convex portion 311 includes the first convex portion 314 and the second convex portion 214, but the convex portion 311 may be one of the first convex portion 314 and the second convex portion 214.

[0073] The first protrusion 314 has a first inclined surface (inclined surface of the first protrusion 314) 314a. The first inclined surface 314a is provided on the inside in the axial direction of the first protrusion 314 (i.e., on the side of the first bent piece 203). The first inclined surface 314a is inclined inward in the axial direction at an inclination angle θ2 as it moves radially inward. That is, the first inclined surface 314a is inclined at the same inclination angle θ2 as the first inclined surface 214a of the second protrusion 214. By setting the first inclined surface 314a and the first inclined surface 214a to the same inclination angle θ2, the first bent piece 203 and the second bent piece 205 can be inserted into the pipe P in the same condition, as in the first embodiment, and the ultimate tensile strength for the pipe P can be appropriately ensured.

[0074] Furthermore, the inclination angle θ2 of the first inclined surface 314a is smaller than the inclination angle θ1 of the first bent piece 203. Furthermore, the inclination angle θ2 of the first inclined surface 214a is also smaller than the inclination angle θ1 of the second bent piece 205. Therefore, similar to the first embodiment, the amount of penetration into the pipe P by the first bent piece 203 and the second bent piece 205 can be increased. This allows the first bent piece 203 and the second bent piece 205 to appropriately ensure the ultimate tensile strength of the pipe P.

[0075] According to the pipe joint 300 according to the second embodiment described above, it is possible to obtain the same effects as those of the first embodiment. That is, when excessive tensile force F is applied to the pipe P, the convex portion 311 can prevent the bent piece 201 of the retaining ring 104a from deforming and turning over in the direction in which the pipe P is removed. This prevents the pipe P from coming out of the pipe fitting 300, or from slipping out completely.

[0076] Furthermore, according to the pipe joint 300 according to the second embodiment, the following advantageous effects can be obtained in addition to the advantageous effects of the pipe joint 100 according to the first embodiment. That is, ring 305 is disposed between nut 302 and first retaining ring 104c. Furthermore, ring 305 is provided with first protrusion 314. Therefore, there is no need to provide nut 302 with a first protrusion. In other words, there is no need to prepare a dedicated nut with a first protrusion for pipe fitting 300. This allows existing nuts 302 that are provided in ordinary pipe fittings to be used with pipe fitting 300.

[0077] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0078] For example, the nut 102 and the water stop portion 103 may be omitted. There may be one retaining ring 104a.

[0079] In addition, the components in this embodiment can be replaced with well-known components as appropriate, without departing from the spirit of the present invention.

[0080] (Addendum) The embodiment can be understood, for example, as follows.

[0081] <1> A pipe fitting according to one aspect of the present invention comprises a cylindrical fitting body, a retaining ring arranged on the inner surface of the fitting body and having a bent piece that inclines inward in the axial direction of the fitting body, and a convex portion arranged on the outside in the axial direction of the bent piece and having an inclined surface that inclines inward in the axial direction as it extends radially inward.

[0082] According to the pipe fitting, the convex portion is disposed axially outward relative to the bent piece. Furthermore, the inclined surface of the convex portion is inclined axially inward as it extends radially inward. Therefore, the convex portion can, for example, keep the bent piece of the retaining ring inclined in the opposite direction to the pipe removal direction. Therefore, for example, if excessive tension is applied to the pipe at a construction site, the convex portion can prevent the bent piece of the retaining ring from deforming in the pipe removal direction and flipping over. This prevents the pipe from slipping out of the pipe fitting (specifically, from slipping out completely). Hereinafter, the pipe slipping out completely may be referred to as "pipe slipping out."

[0083] <2> the above <1> In the pipe fitting according to the above, the retaining ring may include a first retaining ring arranged on the insertion side of the pipe, and a second retaining ring arranged on the opposite side of the insertion side from the first retaining ring, and the convex portion may include a first convex portion arranged on the outside in the axial direction from the first retaining ring, and a second convex portion arranged between the first retaining ring and the second retaining ring.

[0084] The pipe fitting is provided with a first retaining ring and a second retaining ring. Therefore, when excessive tension is applied to the pipe, the two bent pieces can bite into the pipe. This ensures an appropriate ultimate tensile strength for the pipe and prevents the pipe from slipping out.

[0085] <3> the above <2> The pipe fitting according to the above aspect may further include a nut that is threaded onto the fitting body, and an auxiliary spacer ring that is disposed between the first retaining ring and the second retaining ring, and the first convex portion may be provided on the nut, and the second convex portion may be provided on the auxiliary spacer ring.

[0086] According to the pipe fitting, the first convex portion is provided on the nut and the second convex portion is provided on the auxiliary spacer ring. The nut and the auxiliary spacer ring are existing parts that are provided on ordinary pipe fittings. This makes it possible to provide the first convex portion and the second convex portion without increasing the number of parts of the pipe fitting.

[0087] <4> the above <2> In the pipe joint according to the above, the inclined surface of the first convex portion and the inclined surface of the second convex portion may have the same inclination angle.

[0088] If the inclination angles of the first and second convex portions are different, the bent pieces of the first and second retaining rings will bite into the pipe differently, and the amount of penetration into the pipe (depth of penetration into the pipe) will also differ. Therefore, if excessive tensile force is applied to the pipe, for example, one of the two bent pieces will not bite into the pipe sufficiently, reducing the ultimate tensile strength of the pipe.

[0089] Therefore, the inclination angles of the first convex portion and the second convex portion are made the same. Therefore, when excessive tensile force is generated in the pipe, the two bending pieces can be maintained at the same inclination angle in the first convex portion and the second convex portion. In other words, the two bending pieces can be made to bite into the pipe in the same state. Furthermore, the amount of penetration into the pipe by the two bending pieces can be ensured to be the same. This allows the two bending pieces to be made to bite into the pipe in the same state, and the ultimate tensile strength of the pipe can be appropriately ensured.

[0090] <5> the above <3> In the pipe fitting according to the above, the angle of inclination of the second convex portion may be smaller than the angle of inclination of the bent piece of the second retaining ring.

[0091] According to the pipe fitting, the inclination angle of the second convex portion is smaller than the inclination angle of the bent piece of the second retaining ring. Therefore, when excessive tensile force is applied to the pipe, the bent piece of the second retaining ring can bite into the pipe to a greater extent than when the pipe is inserted. This allows the bent piece of the second retaining ring to appropriately ensure the ultimate tensile strength of the pipe.

[0092] <6> the above <3> or <5> In the pipe joint according to the above, the thickness of the auxiliary spacer ring may be 0.5 mm or more and 3 mm or less.

[0093] According to the pipe joint, the thickness of the auxiliary spacer ring is set to 0.5 mm or more and 3 mm or less. This allows the first retaining ring and the second retaining ring to be positioned with an appropriate distance between them in the axial direction. This allows the bent pieces of the first retaining ring and the bent pieces of the second retaining ring to be spaced apart in the axial direction and to bite into the pipe. Therefore, if excessive tensile force is applied to the pipe, the pipe can be prevented from breaking at the point where the bent pieces bite into it. Furthermore, by arranging the first retaining ring and the second retaining ring at an appropriate distance in the axial direction, the insertion distance of the pipe can be appropriately reduced, thereby preventing the pipe from being insufficiently inserted into the pipe fitting when the pipe is inserted into the pipe fitting.

[0094] In contrast, if the thickness of the auxiliary spacer ring is less than 0.5 mm, the first and second retaining rings are positioned close to each other in the axial direction. This means that the bent pieces of the first and second retaining rings tend to bite into the same part of the pipe in the axial direction. Therefore, if excessive tension is applied to the pipe, the pipe is likely to break at the point where the two bent pieces bite into each other.

[0095] Furthermore, if the thickness of the auxiliary spacer ring exceeds 3 mm, the distance between the first retaining ring and the second retaining ring becomes longer. This increases the insertion distance of the pipe when inserting it into the pipe fitting. This can result in the pipe not being fully inserted into the pipe fitting.

[0096] <7> the above <2> or <4> The pipe fitting according to the above aspect may further include a nut threaded onto the fitting body, an auxiliary spacer ring disposed between the first retaining ring and the second retaining ring, and a ring disposed between the nut and the first retaining ring, wherein the first convex portion is provided on the ring, and the second convex portion is provided on the auxiliary spacer ring.

[0097] According to the pipe joint, a ring is disposed between the nut and the first retaining ring. Furthermore, a first convex portion is provided on the ring. Therefore, it is not necessary to provide a first convex portion on the nut. In other words, it is not necessary to prepare a dedicated nut with a first convex portion for the pipe joint. This allows existing nuts provided on ordinary pipe joints to be used with the pipe joint. [Explanation of symbols]

[0098] 100,300...Pipe fittings 101...Joint body 102,302...Nut 104,304…Fixed part 104a...Retaining ring 104b...Auxiliary spacer ring 104c...First retaining ring 104d...Second retaining ring 106... Storage recess 201...Bending piece 203...first bent piece 205...Second bent piece (bent piece of second retaining ring) 211,311...Convex part 212,314...First convex part 212a, 314a...First inclined surface (inclined surface of first convex portion) 214...Second convex part 214a...First inclined surface (inclined surface of second convex portion) 305...Ring P...Pipe θ1...Inclination angle of the second bent piece (inclination angle of the bent piece of the second retaining ring) θ2: Inclination angle of the first convex portion and the second convex portion

Claims

1. A joint body; a retaining ring disposed on an inner peripheral surface of the joint body and having a bent piece inclined inward in the axial direction of the joint body; a convex portion that is arranged on the outside in the axial direction relative to the bent piece and has an inclined surface that inclines inward in the axial direction as it extends radially inward.

2. The retaining ring is a first retaining ring disposed on the insertion side of the tube; a second retaining ring disposed on the opposite side of the insertion side from the first retaining ring, The convex portion is a first protrusion disposed on the outer side of the first retaining ring in the axial direction; 2. The pipe fitting according to claim 1, further comprising: a second protrusion disposed between the first retaining ring and the second retaining ring.

3. a nut that is threadedly attached to the joint body; an auxiliary spacer ring disposed between the first retaining ring and the second retaining ring, The first protrusion is The nut is provided with The second protrusion is 3. The pipe fitting of claim 2, wherein the auxiliary spacer ring is provided.

4. 3. The pipe joint according to claim 2, wherein the inclined surface of the first convex portion and the inclined surface of the second convex portion have the same inclination angle.

5. The inclination angle of the second convex portion is 4. A pipe joint according to claim 3, wherein the angle of inclination of the bent piece of the second retaining ring is smaller than the angle of inclination of the bent piece of the second retaining ring.

6. 6. A pipe joint according to claim 3 or claim 5, wherein the thickness of the auxiliary spacer ring is 0.5 mm or more and 3 mm or less.

7. a nut that is threadedly attached to the joint body; an auxiliary spacer ring disposed between the first retaining ring and the second retaining ring; a ring disposed between the nut and the first retaining ring, The first protrusion is provided on the ring, The second protrusion is 5. The pipe joint according to claim 2 or claim 4, wherein the auxiliary spacer ring is provided.

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