Flexible pipe connector and manufacturing method therefor

Abstract

To provide a flexible pipe connector to simplify a welding structure of the flexible pipe connector to which a fluid transport pipe is connected, improve welding quality, and minimize damage from friction due to vibration.SOLUTION: The flexible pipe connector includes: a corrugated pipe 10; an end ring 20 inserted and welded into an inner side of a front end portion of the corrugated pipe; a circular ring 70 disposed on an outer side of the front end portion of the corrugated pipe; a braided net 30 that covers a portion of an outer circumferential surface of the end ring, an outer circumferential surface of the corrugated pipe, and an outer circumferential surface of the circular ring; and a welding ring configured such that the front end portion of the corrugated pipe is disposed in a gap formed between the welding ring and the end ring.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The present invention relates to a flexible pipe connector for connecting fluid transport pipes, and more particularly to a flexible pipe connector in which a braided mesh made of steel wires is attached to the outside of a metallic corrugated pipe (pleated pipe) to prevent the corrugated pipe from cracking or bursting and to absorb vibrations, and a method for manufacturing the same. [Background technology]

[0002] When connecting a pipe for transporting a fluid to a specific device or when connecting pipes for transporting a fluid to each other, bending may occur in the pipe or its connector during use or due to the narrowness of the installation location. In such cases, flexible pipe connectors are used that have a certain degree of flexibility so that they will not burst or be damaged even when bent.

[0003] For example, flexible pipe connectors are used for piping that supplies high-pressure fluids such as refrigerants for air conditioners, combustion gases for heating appliances, or fire extinguishing liquids.

[0004] The flexible pipe connector includes a corrugated pipe with alternating valleys and peaks through which fluid passes, and a braided mesh made of stainless steel wire that covers the corrugated pipe to prevent the corrugated pipe from stretching or bursting.

[0005] However, in the conventional technology, incomplete welding occurs between the braided mesh and the base material of the welding part, the welding structure is complicated, and the number of work processes and components required for welding is large, which increases the manufacturing cost and manufacturing time of the flexible pipe connector.

[0006] In addition, the conventional technology has a problem that components collide with each other during vibration, resulting in damage to the components. If the hardness of the corrugated pipe does not reach or exceeds a predetermined range, the corrugated pipe cannot absorb vibrations and may bend or burst.

[0007] In particular, when a flexible pipe connector is installed in a device that is subject to continuous vibration, the tip of the metal corrugated pipe and the braided mesh covering the tip of the corrugated pipe are severely rubbed by the vibration, causing cracks to form at the tip of the corrugated pipe, resulting in a problem of refrigerant leaking out of the corrugated pipe.

[0008] Furthermore, among conventional flexible pipe connectors, those in which components are welded together using a silver rod gas welding method are inconvenient in that the components to be welded together must be welded separately at each welding location. In addition, during the welding process, surface roughness and welding stress occur at and around the weld bead, and over time, grain boundary carbon deposition and crack corrosion gradually occur at the welded location, making the connector brittle.

[0009] Meanwhile, in corrugated pipes used to transport fluids, vibrations from the compressor that compresses the refrigerant gas can be transmitted to the closed-circuit piping. Specifically, the welding stress (welding stress of thin-plate straight pipes) and corrugation processing stress (the formation of martensite structure) that occur during the manufacturing process of the corrugated pipes can cause stress corrosion and hardness to increase to 240Hv or more, resulting in insufficient bending flexibility of the corrugated pipes. Furthermore, if the length of the corrugated pipe is short, the vibration absorption rate is insufficient, and vibrations are transmitted to the closed-circuit piping, defeating the purpose of the flexible pipe connectors.

[0010] To solve this problem, an annealing heat treatment process can be added to the manufacturing process to obtain a corrugated pipe with improved elasticity and vibration absorption.

[0011] However, while the conventional manufacturing process that adds an annealing heat treatment process can remove welding stress and processing stress, the increased flexibility of the corrugated pipe causes bending due to the amplitude of vibration in the corrugated pipe adjacent to the compressor (or pump) where vibration occurs. This phenomenon accumulates for the number of vibrations, causing localized and concentrated processing stress at the bent parts, resulting in the fatal problem of crack corrosion. Summary of the Invention [Problem to be solved by the invention]

[0012] The problem to be solved by the present invention is to solve the above-mentioned problems of the prior art.

[0013] Another problem to be solved by the present invention is to provide a flexible pipe connector and a manufacturing method thereof that simplifies the welding structure of the flexible pipe connector, improves welding quality, and reduces production costs.

[0014] Another problem to be solved by the present invention is to provide a flexible pipe connector and a manufacturing method thereof that allows a corrugated pipe and an end ring to be tightly joined together.

[0015] Another object of the present invention is to provide a flexible pipe connector and a manufacturing method thereof that can reduce friction between the corrugated pipe and the braided mesh covering the corrugated pipe even when large and small vibrations are continuously generated, thereby preventing cracks from occurring in the corrugated pipe, thereby preventing damage to the corrugated pipe and the braided mesh even during long-term use, thereby increasing product reliability and extending the product life.

[0016] Yet another object of the present invention is to provide a flexible pipe connector and a manufacturing method thereof that can improve work efficiency by allowing a welding ring to be easily inserted into the end of a braided mesh.

[0017] Another object of the present invention is to provide a flexible pipe connector and a method for manufacturing the same, which can perform brazing welding between components at the same time by performing a single heating process in a heat treatment furnace, and simultaneously perform a work hardening heat treatment process to remove stresses generated during welding or metal processing.

[0018] Another problem that the present invention aims to solve is that corrugated pipes produced using a conventional manufacturing process that involves an annealing heat treatment process have a Vickers hardness of 160HV to 170HV and are too flexible, resulting in low spring elasticity, making them unsuitable for vibration-absorbing corrugated pipes. The present invention aims to eliminate the welding stress and work hardening that occur in the manufacturing process of closed-end corrugated pipes, and to provide an annealing heat treatment hardness that increases the spring elasticity of the corrugated pipes.

[0019] The objects of the present invention are not limited to those mentioned above, and other objects not mentioned will be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0020] To achieve the above object, one embodiment of the present invention provides a flexible pipe connector comprising a corrugated pipe, an end ring having one side inserted into and welded to the inside of the tip of the corrugated pipe, a braided mesh woven with steel wires that covers a portion of the outer surface of the end ring and the outer surface of the corrugated pipe, and a welding ring having an expanded portion formed on one side, inserted into the end ring so that the tip of the braided mesh is positioned in the gap between the expanded portion and the end ring, and to which the tip of the braided mesh is welded.

[0021] Meanwhile, a method for manufacturing a flexible pipe connector according to an embodiment of the present invention for achieving the above object includes the steps of applying a welding agent to a tip of a corrugated pipe and inserting one side of an end ring into the tip; covering a portion of the outer surface of the end ring and the corrugated pipe with a braided mesh and applying a welding agent to an end of the braided mesh; inserting a welding ring into the end ring so that the expanded portion of the welding ring covers the tip of the braided mesh; and heating the assembly of the corrugated pipe, end ring, braided mesh, and welding ring in a heat treatment furnace to melt the welding agent, and then cooling.

[0022] To achieve the above object, a flexible pipe connector according to one embodiment of the present invention includes a corrugated pipe, an end ring having one side inserted into and welded to the inside of the tip of the corrugated pipe, a circular ring placed on the tip of the corrugated pipe, a braided mesh woven with steel wires that covers a portion of the outer surface of the end ring, the outer surface of the corrugated pipe, and the outer surface of the circular ring, and a weld ring inserted outside the end ring, into a gap formed between the end ring and the braided mesh, and into which an end of the braided mesh is inserted and welded.

[0023] The circular ring is disposed so as to protrude outward from the peaks of the corrugated pipe.

[0024] The circular ring may be partially inserted into a valley between the most end peak formed at one end of the corrugated pipe and the peak adjacent to the most end peak, i.e., inside the valley formed at the most end of the corrugated pipe.

[0025] The circular ring may be disposed between the crest at the most distal end of the corrugated pipe and the weld ring.

[0026] The circular ring may be a spring ring with one side cut out.

[0027] The welding ring may have an expanded portion formed on one side thereof, and an end of the braided mesh may be inserted into a gap between the expanded portion and the end ring and welded thereto.

[0028] In addition, the end ring may have a step portion on one side thereof that is smaller in outer diameter than the other side thereof, the step portion of the end ring may be welded to the tip of the corrugated pipe, a step jaw portion may be formed between the other end of the end ring and the step portion, upper and lower extension portions may be formed at the very end of the end of the corrugated pipe, and the step jaw portion of the end ring may be welded to the upper and lower extension portions of the corrugated pipe.

[0029] Further, the end of the braided netting may be temporarily attached to the outer circumferential surface of the end ring using a super glue.

[0030] The tip of the expanded portion of the weld ring may be formed into an inclined surface whose inner circumferential surface has a diameter that gradually decreases toward the inside.

[0031] Meanwhile, a manufacturing method of a flexible pipe connector according to an embodiment of the present invention for achieving the above object includes the steps of applying a welding agent to a tip of a corrugated pipe and inserting one side of an end ring into the inside of the tip; placing a circular ring on the tip of the corrugated pipe; covering a portion of the outer surface of the end ring and the corrugated pipe with a braided mesh and applying a welding agent to an end of the braided mesh; and inserting a welding ring into the end ring so that the welding ring covers the end of the braided mesh.

[0032] After the above steps are completed, the method may include heating the assembly of the corrugated pipe, end rings, braided mesh, and weld ring in a heat treatment furnace so that the welding material melts, and then cooling the assembly.

[0033] In addition, the stepped portion of the end ring may be inserted into the end of the corrugated pipe in an interference fit manner, and the weld ring may be sandwiched and welded to the outer portion of the end ring.

[0034] In addition, the end of the braided mesh may be inserted into the inner circumferential surface of the expanded portion of the welding ring, which has a larger outer diameter than the other end portion. The expanded portion of the welding ring, the outer diameter portion of the end ring, and the end of the braided mesh may be welded together.

[0035] Also, a step portion formed between the step portion and the other side portion of the end ring can be inserted into the inner side of the end portion of the corrugated pipe and welded.

[0036] Furthermore, the welding ring can be processed so that the portion that covers the tip of the braided netting is formed as an expanded portion, and the inner peripheral surface of the tip of the expanded portion is formed as an inclined surface.

[0037] Further, the method may further include temporarily adhering the end of the braided mesh to the outer circumferential surface of the end ring with a metal instant adhesive before the welding ring is inserted into the end ring.

[0038] In addition, the expansion portion of the welding ring is formed with a relatively large inner diameter, and after the tip of the braided mesh is inserted, the expansion portion is crimped, thereby minimizing the welding gap between the expansion portion and the tip of the braided mesh.

[0039] In addition, in order to prevent cracks from occurring at the crests of the corrugated pipe due to friction between the outer part (crests) of the corrugated pipe and the braided mesh caused by vibration, a plate-shaped ring, a circular ring, or an elliptical ring may be sandwiched between the corrugated pipe and the braided mesh.

[0040] In addition, the flexible pipe connector according to the present invention can be heated to 1050°C to 1150°C for a predetermined time in a heat treatment furnace and then cooled, so that welding of each component, corrugated pipe processing and stress relief processes can be completed simultaneously.

[0041] Specific details of other embodiments are included in the detailed description and drawings. [Effects of the Invention]

[0042] The flexible pipe connector and method of manufacturing the same according to the embodiments of the present invention have one or more of the following advantages.

[0043] First, in the flexible pipe connector according to the present embodiment, a circular ring that protrudes outward from the crests of the corrugated pipe is disposed at the tip of the corrugated pipe, or a plate-shaped ring that is disposed outside the crests of the corrugated pipe, and a braided mesh is then placed over the corrugated pipe. This prevents the problem of the crests of the corrugated pipe being worn and damaged (e.g., holes or cracks) due to friction between the adjacent braided mesh and the corrugated pipe, even in an environment where continuous vibration occurs for a long period of time.

[0044] Second, in the flexible pipe connector according to an embodiment of the present invention, a step portion and a step jaw portion are formed on the outer peripheral surface of the end ring, and the tip of the corrugated pipe is welded while abutting the step jaw portion, so that the attachment state between the end ring and the corrugated pipe is reliably maintained even when vibration or impact occurs for a long period of time.

[0045] Third, the inner peripheral surface of the tip of the welding ring is formed into an inclined surface, and the right-angled portion of the tip of the welding ring that comes into contact with the braided mesh is eliminated, so that the tip of the braided mesh can be easily inserted along the expanding inclined surface of the welding ring. Not only that, even if vibration, impact, or bending occurs for a long time, the inner peripheral surface of the tip of the welding ring that comes into contact with the braided mesh is formed into an inclined surface that is not at a right angle, so that the braided mesh is prevented from breaking, bursting, or cracking due to friction with the outer peak of the corrugated pipe.

[0046] Fourth, since the end of the braided mesh is bonded to the end ring and then inserted into the welding ring, the steel wire located at the end of the braided mesh can be easily inserted neatly into the welding ring.

[0047] Fifth, the flexible pipe connector of the present invention, after the assembly of the components, is heated in a heat treatment furnace to the melting temperature of the welding material, which is within the annealing temperature range for stress relief of the corrugated pipe, so that the heat treatment process for relieving processing stress and welding stress of the corrugated pipe and the welding process can be easily performed simultaneously.

[0048] The effects of the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims. [Brief explanation of the drawings]

[0049] [Figure 1] 1 is a front view showing a partially cut-away state of a flexible pipe connector according to a first embodiment of the present disclosure. [Figure 2] 3A and 3B are a perspective view and a cross-sectional view of an end ring. [Figure 3] 3A and 3B are a perspective view and a cross-sectional view of an end ring. [Figure 4]1A and 1B are perspective and cross-sectional views of a weld ring. [Figure 5] 1A and 1B are perspective and cross-sectional views of a weld ring. [Figure 6] 1A to 1C are cross-sectional views showing manufacturing stages of a flexible pipe connector according to a first embodiment of the present disclosure. [Figure 7] 1A to 1C are cross-sectional views showing manufacturing stages of a flexible pipe connector according to a first embodiment of the present disclosure. [Figure 8] 1A to 1C are cross-sectional views showing manufacturing stages of a flexible pipe connector according to a first embodiment of the present disclosure. [Figure 9] 1A to 1C are cross-sectional views showing manufacturing stages of a flexible pipe connector according to a first embodiment of the present disclosure. [Figure 10] FIG. 4 is a cross-sectional view showing a second embodiment of the present disclosure. [Figure 11] FIG. 10 is a front view showing a partially cut-out state of a flexible pipe connector according to a third embodiment of the present disclosure. [Figure 12] FIG. 10 is a perspective view of a circular ring provided in a flexible pipe connector according to third to fifth embodiments of the present disclosure. [Figure 13] 10A to 10C are cross-sectional views showing manufacturing stages of a flexible pipe connector according to a third embodiment of the present disclosure. [Figure 14] 10A to 10C are cross-sectional views showing manufacturing stages of a flexible pipe connector according to a third embodiment of the present disclosure. [Figure 15] 10A to 10C are cross-sectional views showing manufacturing stages of a flexible pipe connector according to a third embodiment of the present disclosure. [Figure 16] 10A to 10C are cross-sectional views showing manufacturing stages of a flexible pipe connector according to a third embodiment of the present disclosure. [Figure 17] FIG. 10 is a cross-sectional view showing a fourth embodiment of the present disclosure. [Figure 18] FIG. 10 is a cross-sectional view showing a fifth embodiment of the present disclosure. [Figure 19] FIG. 10 is a partially cutaway perspective view of a plate-shaped ring provided in a flexible pipe connector according to sixth and seventh embodiments of the present disclosure. [Figure 20] 10A and 10B are cross-sectional views showing a manufacturing stage of a flexible pipe connector according to a sixth embodiment of the present disclosure. [Figure 21] 10A and 10B are cross-sectional views showing a manufacturing stage of a flexible pipe connector according to a sixth embodiment of the present disclosure. [Figure 22] 10A and 10B are cross-sectional views showing a manufacturing stage of a flexible pipe connector according to a sixth embodiment of the present disclosure. [Figure 23] 10A and 10B are cross-sectional views showing a manufacturing stage of a flexible pipe connector according to a sixth embodiment of the present disclosure. [Figure 24] FIG. 10 is a cross-sectional view showing a seventh embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0050] The advantages and features of the present invention, and methods for achieving them, will become apparent from the following detailed description of the embodiments in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, and may be embodied in various different forms. These embodiments are provided solely to complete the disclosure of the present invention and to fully convey the scope of the invention to those skilled in the art. The present invention is defined solely by the claims. Like reference numerals refer to like elements throughout the specification.

[0051] Throughout this specification, when we say that one part is "on" or "on top of" another part, this includes not only "directly on top" of the other part, but also when there is another part between them. Conversely, when we say that one part is "directly on top" of another part, it means that there is no other part between them.

[0052] Furthermore, terms such as "under," "below," "on," and "above" are used to describe the relationship of features shown in the drawings. The terms are relative concepts and are described based on the orientation shown in the drawings.

[0053] When a component is referred to as being "coupled" or "connected" to another component, it should be understood that the component may be directly coupled or connected to the other component, but that there may be other components in between. Conversely, when a component is referred to as being "directly coupled" or "directly connected" to the other component, it should be understood that there may be no other components in between.

[0054] In this application, terms such as "may include" or "have" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0055] A singular expression may include a plural expression unless the context clearly indicates otherwise.

[0056] Hereinafter, a flexible pipe connector according to a first embodiment of the present disclosure will be described with reference to FIGS.

[0057] Referring to FIG. 1, a flexible pipe connector according to an embodiment of the present invention includes a corrugated pipe 10 having a plurality of alternating peaks and valleys, an end ring 20 connected to at least one of both side ends of the corrugated pipe 10, a braided mesh 30 covering the outer surface of the corrugated pipe 10 and a portion of the outer surface of the end ring 20, and a welding ring 40 inserted into the end ring 20 so as to cover a portion of the outer surface of the end ring 20 and the end of the braided mesh.

[0058] The corrugated pipe 10 may be manufactured using austenitic stainless steels STS 304 and STS 316L. STS 304 contains 0.08% or less of C, 0.5-0.75% of Si, 0.035% or less of P, 8.00-15.00% of Ni, and 17.00-18.00% of Cr, while STS 316L contains 0.03% or less of C, 0.5-0.75% of Si, 0.035% or less of P, 0.03% or less of S, 12.00-15.00% of Ni, 17.00-18.00% of Cr, and 2.00-3.00% of Mo. The temperature range for solution heat treatment for stress relief for STS 304 and STS 316L is 1065°C to 1120°C. On the other hand, the corrugated pipe is preferably manufactured from a material having a Vickers hardness (HV) of 175 to 200. For example, the corrugated pipe 10 can have a hardness in the range of 175 to 185 Vickers hardness (HV).

[0059] The braided mesh 30, end rings 20 and welding rings 40 may also be made of the same material as the corrugated pipe 10.

[0060] In addition, the corrugated pipe 10 may be manufactured to have an upper / lower extension 12 at the very end thereof, extending from the valley of the corrugated pipe 10 in the direction of the crest (upward) or from the crest of the corrugated pipe 10 at the very end in the direction of the valley (downward).

[0061] 2 and 3, the end ring 20 has an overall cylindrical shape, but a step portion 21 is formed such that the outer circumferential surface of one side portion 21 is located inward in the direction of the central axis X of the end ring 20 relative to the outer circumferential surface of the other side portion 22, and a step jaw portion 23, which is a ring-shaped vertical surface extending in the up-down direction, is formed between the step portion 21 and the other side portion 22 of the end ring 20.

[0062] Referring to Figures 4 and 5, the welding ring 40 has an overall cylindrical shape with a stepped central portion 43, but one side portion 41 is formed with an expanded portion 41 having a larger inner diameter than the other side portion 42, and the inner surface 44 of the tip of the expanded portion 41 is formed as an inclined surface whose inner diameter becomes smaller as it goes inward (towards the central portion 43).

[0063] The inclined surface may be formed so that the cross section is inclined in a straight line, or may be formed so that the cross section is inclined in a curved line.

[0064] Meanwhile, the weld ring 40 is formed shorter in left and right length than the end ring 20 so that when inserted into the end ring 20, both ends of the end ring are exposed outside the weld ring 40.

[0065] A method for manufacturing the flexible pipe connector according to the embodiment of the present invention configured as above will be described with reference to FIGS.

[0066] As shown in FIG. 6, the stepped portion 21 of the end ring 20, which has a smaller outer diameter than the other side portion 22, is forcibly inserted into the end of the corrugated pipe 10 so that the upper and lower extensions 12 located at the end of the corrugated pipe 10 are adjacent to the end jaws 23 of the end ring 20.

[0067] In the above, paste welding agent 51 is applied to the inner surface of the tip portion 11 and the upper and lower extension portions 12 of the corrugated pipe 10 so that the tip portion 11 and the upper and lower extension portions 12 of the corrugated pipe 10 can be welded to the step portion 21 and step jaw portion 23 of the end ring 20 later, and then the step portion 21 of the end ring 20 is forcibly inserted into the inside of the tip portion of the corrugated pipe 10.

[0068] Therefore, the upper and lower extensions 12 formed at the ends of the corrugated pipe 10 are welded together while hanging on the stepped jaws 23 of the end rings 20, so that the end rings 20 and the corrugated pipe 10 do not loosen from each other even when subjected to vibrations and shocks that occur over a long period of time, and the bonded state is reliably maintained.

[0069] Next, as shown in Figure 7, the braided mesh 30 is placed over the outer surface of the corrugated pipe 10 so that the tip 31 of the braided mesh 30 is positioned on the outer surface of the other side 22 of the end ring 20, and as shown in Figure 8, the end 31 of the braided mesh 30 is bonded to the outer surface of the end ring 20 using a metal instant adhesive 52, and a paste welding agent 53 is applied to the end of the braided mesh 30.

[0070] Next, as shown in Figure 9, the welding ring 40 is forcibly inserted into the other end 22 of the end ring 20, but the welding ring 40 is inserted into the end ring 20 so that the tip 31 of the braided mesh 30 is positioned in the gap formed between the inner surface of the expanded portion 41 of the welding ring 40 and the outer surface of the end ring 20.

[0071] In the above, the end 31 of the braided mesh 30 is bonded to the end ring 20 using instant adhesive before the welding ring 40 is inserted into the end ring 20. Therefore, the end of the braided mesh 30, particularly the fine steel wires of the braided mesh located at the end, are bonded to the end ring 20 without bulging. As a result, the tip of the welding ring 40 can be easily inserted to a predetermined position in the end ring 20 without interfering with the steel wires of the braided mesh 30. Furthermore, the inner surface of the tip of the welding ring 40 is formed with an inclined surface 44, so the tip of the braided mesh 30 can be smoothly moved to the predetermined position on the welding ring 40.

[0072] Furthermore, the inner peripheral surface of the tip of the welding ring 40 is formed as an inclined surface until it is inserted into the expanded tube portion 41 of the welding ring 40, so that even if vibration or impact occurs for a long period of time, the tip of the braided net 30 does not come into line contact with the tip of the welding ring 40,

[0073] The oblique contact prevents the end of the braided net from being damaged or cut.

[0074] When the corrugated pipe 10, end rings 20, braided mesh 30, and welding ring 40 are placed in a heat treatment furnace and heated and then cooled, the welding agent applied to the ends of the corrugated pipe 10 and the braided mesh 30 melts and solidifies, and the corrugated pipe 10, braided mesh 30, end rings 20, and welding ring 40 are firmly welded together and integrated.

[0075] As the paste welding agents 51 and 53, Ag-Mn based welding agents with a welding temperature of 970°C to 1150°C, Ag-Cu based welding agents with a welding temperature of 990°C to 1090°C, or Ni-Cr based welding agents with a welding temperature of 1090°C to 1180°C, in particular BniCr based welding agents containing 65 to 75 wt% Ni, 13 to 20 wt% Cr, 2.75 to 4.75 wt% B, and trace amounts of Fe, Si, and C, can be used.

[0076] Therefore, when the flexible pipe connector joined as shown in Figure 9 is placed in a heat treatment furnace and heated to a temperature of 1050°C to 1150°C, which is the melting temperature of the welding agents 51 and 53, for a few seconds, the welding agents 51 and 53 melt and stain the welded area, removing the stress and work hardening that occurred during the molding of components such as the corrugated pipe 10, and the instant adhesive disappears.When this is cooled, the welding is completed, and the manufacture of the flexible pipe connector according to the present invention is completed.

[0077] As described above, the flexible pipe connector according to the present invention has advantages in that the components can be tightly and easily connected to each other, and there is no risk of the components becoming loose or damaged due to vibration. In addition, the welding process and the heat treatment process can be carried out simultaneously through a single heating process in a heat treatment furnace, which allows for simple and quick manufacturing.

[0078] Figure 10 is a cross-sectional view showing another embodiment of the present invention, and a flexible pipe connector according to another embodiment of the present invention will be described below with reference to Figure 10. Of the components not described below, those essential for constituting the invention are the same as those in the previously described embodiment of the present invention, and therefore will be omitted.

[0079] Referring to FIG. 10, in another embodiment of the present invention, a connecting ring 60 for connecting a pipe is connected to the end of the end ring 20, and the end of the connecting ring 60 and the end of the end ring 20 are connected by mating stepped portions 65, 25.

[0080] The connection ring 60 may be made of the same material as the pipe to be connected to the flexible pipe fitting, for example Cu.

[0081] Other components not described above are the same as those in the embodiment of the present invention shown in FIGS. 6 to 9, and therefore further description will be omitted.

[0082] A flexible pipe connector according to a third embodiment of the present disclosure will be described below with reference to Figures 11 to 16. Referring to Figures 11 and 24, the flexible pipe connector according to the embodiment of the present disclosure includes a corrugated pipe 10 having a plurality of alternating peaks and valleys, an end ring 20 coupled to at least one of both side ends of the corrugated pipe 10, a protective ring 70, 700 disposed at the tip of the corrugated pipe, a braided mesh 30 covering the outer circumferential surface of the corrugated pipe 10, the protective ring 70, 700, and a portion of the outer circumferential surface of the end ring 20, and a welding ring 40 inserted into the end ring 20 so as to cover a portion of the outer circumferential surface of the end ring 20 and an end of the braided mesh.

[0083] The protective rings 70, 700 can include a circular ring 70 or a plate-shaped ring 700. The flexible pipe connectors according to the third embodiment shown in Fig. 11 to Fig. 16, the fourth embodiment shown in Fig. 17, and the fifth embodiment shown in Fig. 18 can include a circular ring 70, and the flexible pipe connectors according to the sixth embodiment shown in Fig. 19 to Fig. 23 and the seventh embodiment shown in Fig. 24 can include a plate-shaped ring 700.

[0084] As in the previous embodiment, the corrugated pipe 10 can be manufactured from austenitic stainless steels STS304 and STS316L. STS304 contains 0.08% or less of C, 0.5-0.75% of Si, 0.035% or less of P, 8.00-15.00% of Ni, and 17.00-18.00% of Cr, while STS316L contains 0.03% or less of C, 0.5-0.75% of Si, 0.035% or less of P, 0.03% or less of S, 12.00-15.00% of Ni, 17.00-18.00% of Cr, and 2.00-3.00% of Mo. The solution heat treatment temperature range for stress relief for STS304 and STS316L is 1065°C to 1120°C.

[0085] Meanwhile, conventional corrugated pipes have a Vickers hardness (HV) of 200 or more if no heat treatment process is performed in the manufacturing process, and have a Vickers hardness (HV) of 160 to 170 if a heat treatment process is performed in the manufacturing process. The corrugated pipe of the present disclosure is preferably manufactured from a material that has a Vickers hardness (HV) of 175 to 185 by adjusting the cooling temperature and cooling rate in the heat treatment process. This heat treatment method for corrugated pipes has two advantageous effects: it removes welding stress and processing stress generated in the corrugated pipe manufacturing process, and also increases spring elasticity.

[0086] The braided mesh 30, the end rings 20, the circular rings 70 and the welding rings 40 may also be made of the same material as the corrugated pipe 10.

[0087] In addition, the corrugated pipe 10 may be manufactured to have upper and lower extensions 12 extending from the valley of the corrugated pipe 10 located at the end thereof in the direction of the crest (upward) or from the crest of the corrugated pipe 10 located at the end thereof in the direction of the valley (downward).

[0088] The end ring 20 of this embodiment is similar to the end ring 20 of the embodiment described above with reference to FIGS. 2 and 3, and therefore a description thereof will be omitted.

[0089] Referring to FIG. 12, the circular ring 70 may be formed to have a ring-like overall shape and an outer diameter larger than the outer diameter of the crests of the corrugated pipe.

[0090] The circular ring 70 may be formed in an elliptical shape so that its cross section matches the shape of the valley of the corrugated pipe, or alternatively, may be formed in a perfect circle.

[0091] The circular ring 70 may be formed to a size that protrudes outward from the crest when the circular ring is inserted into the trough of the corrugated pipe.

[0092] For example, the outer diameter of the circular ring 70 may be 1 to 2 mm larger than the outer diameter of the crests of the corrugated pipe, and the circular ring 70 may protrude outward from the crests of the corrugated pipe by 0.5 to 1.0 mm.

[0093] The ring 70 may be formed as a spring ring 71 with one side cut out.

[0094] The circular ring 70 may be made of metal or synthetic resin.

[0095] The weld ring 40 of this embodiment is similar to the weld ring 40 of the embodiment described above with reference to FIGS. 4 and 5, and therefore a description thereof will be omitted.

[0096] A method for manufacturing the flexible pipe connector according to the third embodiment of the present disclosure configured as above will be described with reference to FIGS. 6 and 13 to 16. FIG.

[0097] As shown in FIG. 6, the stepped portion 21 of the end ring 20, which has a smaller outer diameter than the other side portion 22, is forcibly inserted into the end of the corrugated pipe 10, and the upper and lower extensions 12 located at the end of the corrugated pipe 10 are inserted adjacent to the end jaws 23 of the end ring 20.

[0098] In the above, paste welding agent 51 is applied to the inner surface of the tip portion 11 and the upper and lower extension portions 12 of the corrugated pipe 10 so that the tip portion 11 and the upper and lower extension portions 12 of the corrugated pipe 10 can be welded to the step portion 21 and step jaw portion 23 of the end ring 20 later, and then the step portion 21 of the end ring 20 is forcibly inserted into the inside of the tip portion of the corrugated pipe 10.

[0099] Therefore, since the upper and lower extensions 12 formed at the ends of the corrugated pipe 10 are welded to the end rings 20 while hanging on the stepped jaws 23 of the end rings 20, the end rings 20 and the corrugated pipe 10 do not loosen from each other even when subjected to vibrations and shocks that occur over a long period of time, and the bonded state is firmly maintained.

[0100] Next, as shown in FIG. 13, the circular ring 70 is placed so as to be inserted into the valley 13 at the end between the peak 11a formed at the end of one side of the corrugated pipe 10 and the peak 11b closest to the peak 11a at the end.

[0101] The circular ring 70 is formed as a spring ring with an incision 71 on one side. The circular ring 70 is forcibly expanded and then placed in the valley 13, so that the circular ring 70 can be inserted into the valley 13 while returning to its circular shape due to its elasticity.

[0102] The circular ring 70 is made of an elastic material and has a closed circular shape without an incision on one side, and can be inserted into the valley.

[0103] Although not shown here, the circular ring may be disposed between the ridge 11b formed at the end of the corrugated pipe and the weld ring 20 described below without being inserted into the valley 13. In this case, a valley (not shown) may be formed in the upper and lower extensions 12, or a valley (not shown) may be formed between the upper and lower extensions 12 and the end ring 20, and a portion of the circular ring may be inserted into the valley or groove to be supported.

[0104] Next, as shown in Figure 14, the braided mesh 30 is placed over the outer surfaces of the corrugated pipe 10 and the circular ring 70 so that the tip 31 of the braided mesh 30 is positioned on the outer surface of the other side 22 of the end ring 20, and as shown in Figure 15, the end 31 of the braided mesh 30 is bonded to the outer surface of the end ring 20 using a metal instant adhesive 52, and a paste welding agent 53 is applied to the end of the braided mesh 30.

[0105] Next, as shown in Figure 16, the welding ring 40 is forcibly inserted into the other side portion 22 of the end ring 20, but the welding ring 40 is inserted into the end ring 20 so that the end 31 of the braided mesh 30 is positioned in the gap formed between the inner surface of the expanded portion 41 of the welding ring 40 and the outer surface of the end ring 20.

[0106] In the above, the end 31 of the braided mesh 30 is bonded to the end ring 20 using instant adhesive before the welding ring 40 is inserted into the end ring 20. Therefore, the fine steel wires of the braided mesh located at the end of the braided mesh 30, particularly at the tip, are bonded to the end ring 20 without bulging. As a result, the tip of the welding ring 40 can be easily inserted to a predetermined position in the end ring 20 without interfering with the steel wires of the braided mesh 30. Furthermore, the inner surface of the tip of the welding ring 40 is formed with an inclined surface 44, so that the end of the braided mesh 30 can be smoothly moved to a predetermined position in the welding ring 40.

[0107] In addition, the inner surface of the tip of the welding ring 40 is formed as an inclined surface until it is inserted into the expanded portion 41 of the welding ring 40, so even if vibration or impact occurs for a long period of time, the tip of the braided mesh 30 makes inclined contact with the tip of the welding ring 40 rather than line contact, preventing the end of the braided mesh from being damaged or cut.

[0108] As described above, the corrugated pipe 10, end rings 20, circular rings 70, braided mesh 30, and welding ring 40 are joined together and coated with fast-type welding agent. When this state is placed in a heat treatment furnace and heated and then cooled, the welding agent coated on the ends of the corrugated pipe 10 and the braided mesh 30 melts and solidifies, and the corrugated pipe 10, braided mesh 30, end rings 20, and welding ring 40 are firmly welded together and integrated.

[0109] As the paste welding agents 51 and 53, Ag-Mn based welding agents with a welding temperature of 970°C to 1150°C, Ag-Cu based welding agents with a welding temperature of 990°C to 1090°C, or Ni-Cr based welding agents with a welding temperature of 1090°C to 1180°C, in particular, BNiCr based welding agents containing 65 to 75 wt% Ni, 13 to 20 wt% Cr, 2.75 to 4.75 wt% B, and trace amounts of Fe, Si, and C, can be used.

[0110] Therefore, when the flexible pipe connector assembled as shown in Figure 16 is placed in a heat treatment furnace and heated for a few minutes at a temperature of 1050°C to 1150°C, which is the melting temperature of the welding agents 51 and 53, the welding agents 51 and 53 melt and penetrate into the welding area, welding it. At the same time, the stress and work hardening (processing stress) generated during the molding of the corrugated pipe 10 are removed, and the instant adhesive disappears. When this is cooled, the welding of each component and the removal of the work hardening of the corrugated pipe are completed simultaneously, and the manufacture of the flexible pipe connector according to the present disclosure is completed.

[0111] As described above, the flexible pipe connector of the present disclosure has the advantage that each component can be tightly and easily connected to each other, and there is no risk of the components loosening or being damaged by vibration. In addition, the welding process and the heat treatment process can be carried out simultaneously through a single heating process in a heat treatment furnace, making it easy and quick to manufacture.

[0112] In particular, the flexible pipe connector according to the third embodiment of the present disclosure has a circular ring protruding from the corrugated pipe between the tip of the corrugated pipe and the braided mesh, which reduces friction between the outer diameter (peak) of the corrugated pipe and the braided mesh even during vibration, preventing damage to the corrugated pipe and improving the reliability and lifespan of the product.

[0113] Fig. 17 is a cross-sectional view showing a fourth embodiment of the present disclosure. Below, a flexible pipe connector according to the fourth embodiment of the present disclosure will be described with reference to Fig. 17. Of the configurations not described below, those essential for constituting the invention are the same as those in the above-described embodiments, and therefore will be omitted.

[0114] Referring to FIG. 17, a connecting ring 60 for connecting a pipe is connected to the tip of the end ring 20 of the fourth embodiment of the present disclosure, and the tip of the connecting ring 60 and the tip of the end ring 20 are firmly connected and connected to each other through stepped portions 65 and 25 that match with each other.

[0115] The connection ring 60 may be made of the same material as the pipe to be connected to the flexible pipe fitting, for example Cu.

[0116] Fig. 18 is a cross-sectional view showing a fifth embodiment of the present disclosure. Hereinafter, a flexible pipe connector according to the fifth embodiment of the present disclosure will be described with reference to Fig. 18. When compared with the fourth embodiment described above, the flexible pipe connector according to the fifth embodiment may differ in the position of the circular ring 70a. Descriptions of configurations and features similar to those of the fourth embodiment will be omitted.

[0117] 18, the circular ring 70a is disposed between the most distal ridge 11a formed on one side of the corrugated pipe and the weld ring 40. More specifically, the circular ring 70a is disposed so as to contact the surface of the most distal ridge 11a facing the weld ring 40.

[0118] Although not shown here, the circular ring is disposed between the most distal crest 11a and the weld ring 40, but it can also be disposed so as to be spaced apart from the most distal crest 11a.

[0119] In the embodiment of FIG. 18, the circular ring 70a may have an outer diameter equal to or smaller than the outer diameter of the crests of the corrugated pipe, and a closed circular ring may also be used.

[0120] On the other hand, as described above, the protective rings 70, 700 may be plate-shaped rings 700 instead of the circular rings 70 of the above-described embodiments.

[0121] 19 to 24, a flexible pipe connector according to a sixth embodiment including a plate-shaped ring 700 will be described below. To facilitate understanding of this embodiment, the same components as those in the previously described embodiment are designated by the same reference numerals, and some of the description thereof will be omitted.

[0122] Referring to FIG. 19, the plate-shaped ring 700 may be formed to have a cylindrical overall shape and an outer diameter larger than the outer diameter of the crests of the corrugated pipe 10 .

[0123] The plate-shaped ring 700 may include a cylindrical body 701 and a ring-shaped locking portion 702 extending radially inward from one end of the body 701 .

[0124] The plate-shaped ring 700 may have a thickness in the range of 0.2 to 0.4 mm. For example, the thickness of the plate-shaped ring 700 may be 0.3 mm.

[0125] In order to insert the corrugated pipe 10 inside the plate-shaped ring 700, the inner diameter of the plate-shaped ring 700 may be formed to be the same as or 1 to 2 mm larger than the outer diameter of the crest of the corrugated pipe.

[0126] Therefore, the outer diameter of the plate-shaped ring 70 can be larger than the outer diameter of the crest of the corrugated pipe.

[0127] The plate-shaped ring 700 may be made of metal or synthetic resin.

[0128] A method for manufacturing a flexible pipe connector including a plate-like ring 700 will be described with reference to Figures 6 and 20 to 23. The description of the same components as in the method for manufacturing the flexible pipe connector of the third embodiment described above with reference to Figures 6 and 13 to 16 may be partially omitted.

[0129] Referring to FIG. 6, in the manufacturing method of this embodiment, the corrugated pipe 10 and the end ring 20 are joined together as described above.

[0130] Next, as shown in FIG. 20, the plate-shaped ring 700 is placed outside the end ring 20 so that the end ring 20 is inserted inside the plate-shaped ring 700.

[0131] The other side portion 22 of the end ring 20 is inserted inside the locking portion 702 of the plate ring 700. The plate ring 700 is slid toward the corrugated pipe 10 so that the end portion 11 of the corrugated pipe 10 is inserted inside the body 701 of the plate ring 700. The plate ring 700 is slid so that the locking portion 702 abuts against the end portion 11 of the corrugated pipe 10.

[0132] Next, as described with reference to FIGS. 14 and 15 and as shown in FIGS. 21 and 22, the braided mesh 30 and the end rings 20 are arranged and bonded, and a paste welding agent 53 is applied to the end of the braided mesh 30.

[0133] Next, the weld ring 40 is inserted into the end ring 20 as shown in FIG. 23 and described with reference to FIG.

[0134] As described above, the corrugated pipe 10, the end ring 20, the circular ring 70, the braided mesh 30, and the welding ring 40 are joined together and coated with a fast-type welding agent. When this is heated in a heat treatment furnace and then cooled, the tip and end of the corrugated pipe 10 are welded.

[0135] The welding agent applied to the end of the braided mesh 30 is melted and then solidified, and the corrugated pipe 10, the braided mesh 30, the end ring 20 and the welding ring 40 are firmly welded together and integrated.

[0136] As shown in Figure 23, when the joined flexible pipe connector is placed in a heat treatment furnace and heated for a few minutes at 1050°C to 1150°C, which is the melting temperature of the welding materials 51 and 53, the welding materials 51 and 53 melt and penetrate into the welding parts, welding them together. In addition, the stress and work hardening (working stress) generated during the formation of the corrugated pipe 10 are removed, and the instant adhesive disappears. When this is cooled, the welding of each component part is completed.

[0137] The work hardening removal of the corrugated pipe is completed at the same time, completing the manufacture of the flexible pipe connector of the present invention.

[0138] In particular, the flexible pipe connector of this embodiment has a plate-shaped ring arranged between the corrugated pipe and the braided mesh, which reduces friction between the outer diameter portion (peak portion) of the corrugated pipe and the braided mesh even during vibration, preventing damage to the corrugated pipe and improving the reliability and lifespan of the product.

[0139] A flexible pipe connector according to a seventh embodiment of the present disclosure will now be described with reference to Fig. 24. Of the configurations not described below, those essential for configuring the present invention are the same as those in the previously described embodiments, and therefore will be omitted.

[0140] Referring to FIG. 24, a connecting ring 60 for connecting a pipe is connected to the tip of the end ring 20 of the seventh embodiment of the present disclosure, and the tip of the connecting ring 60 and the tip of the end ring 20 are firmly connected and connected to each other through stepped portions 65, 25 that match each other.

[0141] The connection ring 60 may be made of the same material as the pipe to be connected to the flexible pipe fitting, for example Cu.

[0142] It will be understood by those skilled in the art that the present invention can be embodied in other specific forms without changing the technical spirit or essential characteristics thereof. Therefore, the above-described embodiments should be understood to be illustrative in all respects and not limiting. The scope of the present invention is defined by the claims set forth below, rather than the above detailed description, and all modifications and variations derived from the meaning and scope of the claims and their equivalents should be construed as being within the scope of the present invention. [Explanation of symbols]

[0143] 10: Corrugated pipe 20: End ring 21: Stepped portion 23: Stepped jaw portion 30: Braided mesh 40: Welded ring 41: Expansion section 44: Inclined surface 51, 53: Welding agent 52: Adhesive 60: Connecting ring 70: Circular ring 700: Plate-shaped ring

Claims

1. Corrugated pipe with alternating peaks and valleys an end ring, one side of which is inserted into and welded to the inside of the end of the corrugated pipe; a protective ring disposed on the outside of the end of the corrugated pipe; a braided mesh covering a portion of the outer peripheral surface of the end ring, the outer peripheral surface of the corrugated pipe, and the outer peripheral surface of the protective ring; a welding ring inserted outside the end ring, into which an end of the braided mesh is inserted and welded to a gap formed between the end ring and the welding ring;

2. 2. The flexible pipe connector of claim 1, wherein the protective ring comprises a circular ring inserted into a valley formed in the end of the corrugated pipe.

3. 3. The flexible pipe connector according to claim 2, wherein the circular ring is inserted into a valley formed at the most distal end of valleys formed at the end of the corrugated pipe.

4. 3. A flexible pipe connector according to claim 2, wherein said circular ring is formed of a spring ring having at least one end cut out.

5. 3. The flexible pipe connector according to claim 2, wherein the circular ring protrudes from the crest of the corrugated pipe to the outside of the corrugated pipe.

6. 6. A flexible pipe connector according to claim 5, wherein the outer diameter of the circular ring is 1.0 mm to 2.0 mm larger than the outer diameter of the crests of the corrugated pipe.

7. 2. The flexible pipe connector according to claim 1, wherein the protective ring comprises a plate-shaped ring disposed on the outside of the end of the corrugated pipe.

8. The plate-shaped ring is a body disposed outside the corrugated pipe; 8. A flexible pipe connector according to claim 7, further comprising a locking portion bent radially inward from the end of said body and abutting against the tip end of said corrugated pipe.

9. 2. The flexible pipe connector according to claim 1, wherein the welding ring has an expanded portion formed on one side thereof, and the end of the braided mesh is inserted into a gap between the expanded portion and the end ring.

10. The end ring has a stepped portion on one side thereof having an outer diameter smaller than that of the other side thereof, the stepped portion of the end ring is welded to the tip of the corrugated pipe, a stepped jaw portion is formed between the other end of the end ring and the stepped portion, upper and lower extension portions are formed at the very end of the end of the corrugated pipe, and the stepped jaw portion of the end ring is welded to the upper and lower extension portions of the corrugated pipe.

11. 10. A flexible pipe connector according to claim 9, wherein the tip of the expanded pipe portion of the weld ring is formed as an inclined surface whose inner circumferential surface has a diameter that decreases toward the inside.

12. the corrugated pipe, end rings, protective rings, braided mesh, and weld ring are made of austenitic stainless steel; 12. The flexible pipe connector according to claim 11, wherein the corrugated pipe and the end ring, and the welding ring and the braided mesh are welded together using an Au-Mn based, Ag-Cu based, or Ni-Cr based welding agent.

13. 2. The flexible pipe connector according to claim 1, wherein the corrugated pipe has a Vickers hardness of 175 to 185.

14. applying a welding agent to the end of the corrugated pipe and inserting one side of an end ring into the end; before or after the step, placing a protective ring on the end of the corrugated pipe; a step of covering a portion of the outer circumferential surface of the end ring, the corrugated pipe, and the protective ring with a braided mesh, and applying a welding agent to an end of the braided mesh; inserting a weld ring into the end ring such that an enlarged portion of the weld ring covers an end of the braided mesh; a step of heating the assembly of the corrugated pipe, the protective ring, the end ring, the braided mesh and the welding ring in a heat treatment furnace to melt the welding material, and then cooling the assembly;

15. 15. The method of claim 14, wherein the step of positioning the protective ring includes inserting a circular ring into a valley formed in the end of the corrugated pipe.

16. 15. The method for manufacturing a flexible pipe connector according to claim 14, wherein the step of positioning the protective ring includes a step of positioning the plate-shaped ring so that a body of the plate-shaped ring is positioned outside the corrugated pipe and a locking portion bent radially inward from the body of the plate-shaped ring abuts against an end of the corrugated pipe.

17. 15. A method for manufacturing a flexible pipe connector as described in claim 14, wherein the end ring has a stepped portion formed with a smaller outer diameter than the other side portion, and the valley portion of the tip of the braided mesh is welded to the outer peripheral surface of the stepped portion, which is formed with a smaller outer diameter than the other side portion, and upper and lower extension portions located at the very end of the corrugated pipe are welded to the stepped jaw portion formed between the stepped portion and the other side portion of the end ring.

18. 15. The method for manufacturing a flexible pipe connector according to claim 14, wherein the end of the braided mesh is bonded to the outer circumferential surface of the end ring with an instant metal adhesive before the weld ring is inserted into the end ring.

19. A method for manufacturing a flexible pipe connector as described in claim 15, wherein the flexible pipe connector is heated in a heat treatment furnace at 1050°C to 1150°C for a predetermined period of time, and then cooled, and the welding process and the metal heat treatment process are performed simultaneously.

20. 16. The method for manufacturing a flexible pipe connector according to claim 15, wherein the tip of the weld ring is machined to form an inclined inner circumferential surface whose inner diameter decreases inward.

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