Method for manufacturing pipe with resin joint

Abstract

This method for manufacturing a pipe with a resin joint is provided with: a pretreatment step for roughening the outer surface of the end (11E) of a metal pipe (11); a first attachment step for attaching a resin joint (12) to the roughened end (11E); a heating step in which, in a state in which the resin joint (12) is attached to the metal pipe (11), a portion where the metal pipe (11) and the resin joint (12) are attached is heated; a pressing step for pressing the resin joint (12) from the outside of the resin joint (12) to the inside of the metal tube (11); a cooling step for cooling the resin joint (12); and a second mounting step for mounting a reinforcing member (13) on the outer surface of the resin joint (12) after the resin joint (12) is cooled. The linear expansion coefficient of the reinforcing member (13) is smaller than the linear expansion coefficient of the resin joint (12).

Description

Technical Field

[0001] This invention relates to a method for manufacturing a pipe with resin fittings. Background Technology

[0002] Previously, methods for joining different types of materials with high bonding strength or high sealing performance have been proposed. For example, Patent Document 1 describes a method for joining a metal molded body and a resin molded body. In the method described in Patent Document 1, after roughening the metal molded body, the resin molded body is pressed against the roughened first roughened portion, and the surface of the resin molded body corresponding to the first roughened portion is fused with the first roughened portion. Existing technical documents Patent documents

[0003] Patent Document 1: Japanese Patent Application Publication No. 2022-30445 Summary of the Invention The problem that the invention aims to solve

[0004] The joining of different types of materials is also used in cases where pipes of different types of materials are connected to each other. For example, in the case of connecting a metal pipe to a resin pipe, a resin fitting is sometimes used. In this case, the resin fitting is joined to the metal pipe, which is a different type of material from it.

[0005] Such a structure could also be used, for example, in vehicle piping. In this case, the vehicle interior is hot, and fluids such as refrigerant from the vehicle's air conditioning system flow under high pressure within the piping for extended periods. Even under such harsh conditions, it is desirable to maintain a high level of sealing at the joints between different types of materials, such as resin fittings and metal pipes.

[0006] The inventors of this application manufactured a pipe with a resin fitting by roughening a metal pipe and attaching a resin fitting to the roughened portion, as described in prior art document 1. Furthermore, experiments simulating harsh conditions inside a vehicle were conducted using the pipe with the resin fitting. The results showed that fluid flowing in the pipe leaked between the resin fitting and the metal pipe.

[0007] The purpose of this invention is to provide a method for manufacturing a pipe with a resin-coated joint that has high sealing performance. Methods for solving problems

[0008] The manufacturing method of the pipe with a resin connector disclosed in this specification is a method for manufacturing a pipe with a resin connector that is joined to a metal pipe, comprising: a pretreatment step of roughening the outer surface of the end of the metal pipe; a first mounting step of mounting a cylindrical resin connector on the roughened end of the metal pipe; a heating step of heating the mounting portion of the metal pipe and the resin connector while the resin connector is mounted on the end of the metal pipe; a pressing step of pressing the resin connector from the outside of the resin connector toward the inside of the metal pipe while the mounting portion of the metal pipe and the resin connector is heated; a cooling step of cooling the resin connector after pressing it toward the inside of the metal pipe; and a second mounting step of mounting a reinforcing member on the outer surface of the resin connector on the outside of the end of the metal pipe after cooling, wherein the coefficient of linear expansion of the reinforcing member is smaller than the coefficient of linear expansion of the resin connector.

[0009] In this specification, "tube" refers to a cylindrical component. In this specification, "tube" includes not only components referred to as "pipe," but also components referred to as "hose" and "tube."

[0010] According to the above method, while the mounting portion of the metal tube and resin connector is heated, the resin connector is pressed from the outside of the resin connector towards the inside of the metal tube. This causes the resin connector to enter multiple recesses on the roughened outer surface of the metal tube end, resulting in a tight fit between the resin connector and the metal tube end with almost no gap. While maintaining this tight fit with almost no gap between the resin connector and the metal tube end, the resin connector is cooled, causing it to cure. After the resin connector has cured in this state, a reinforcing member is installed. Alternatively, the reinforcing member is not installed on the resin connector before it has cured.

[0011] Therefore, even when the resin-fitted joint expands and then contracts due to temperature decrease in a metal tube used at high temperatures, almost no gap is generated between the resin-fitted joint and the reinforcing member. Furthermore, the linear expansion coefficient of the reinforcing member is smaller than that of the resin-fitted joint, thus the reinforcing member can be used to suppress the outward expansion of the resin-fitted joint at high temperatures. Therefore, almost no gap is generated between the resin-fitted joint and the reinforcing member. Thus, even if the resin-fitted joint softens at high temperatures, it can be prevented from peeling off from the metal tube. Therefore, fluid flowing inside the metal tube is less likely to leak between the metal tube and the resin-fitted joint. As described above, it is possible to obtain a pipe with a resin fitting that provides a high level of sealing between the metal tube and the resin fitting.

[0012] In the heating process, the metal tube can be heated by using a heating device, thereby heating the mounting portion of the metal tube and the resin joint.

[0013] By using the above method, it is possible to heat the mounting portion of the metal tube and the resin connector while suppressing heating of parts of the resin connector other than the portion opposite the metal tube, such as the outer surface of the resin connector and the portion connected to other tubes.

[0014] The reinforcing component can be a cylindrical component.

[0015] When the reinforcing component is cylindrical, the outer surface of the resin joint is covered by the reinforcing component. This makes the resin joint less prone to peeling off from the metal tube. Therefore, the sealing performance between the resin joint and the metal tube is further improved.

[0016] In the second installation step, the reinforcing member can be pressed radially toward the resin joint so that the inner surface of the reinforcing member fits tightly against the outer surface of the resin joint.

[0017] This simple method enables the creation of resin joints that are difficult to peel off from metal tubing.

[0018] As another perspective, in the second installation step, the reinforcing member having an inner diameter less than the outer diameter of the resin joint can be pressed axially into the resin joint, so that the inner surface of the reinforcing member is in close contact with the outer surface of the resin joint, thereby positioning the reinforcing member on the outside of the resin joint.

[0019] This simple method enables the creation of resin joints that are difficult to peel off from metal tubing.

[0020] As another perspective, the outer surface of the resin joint has a tapered portion whose outer diameter increases towards one end in the axial direction. The reinforcing member is a cylindrical member, and the inner surface of the reinforcing member has a tapered portion whose inner diameter increases towards one end in the axial direction. In the second installation step, in the axial direction of the resin joint, the direction in which the outer diameter of the resin joint increases is the same as the direction in which the inner diameter of the reinforcing member increases. The reinforcing member is pressed into the resin joint so that the inner surface of the reinforcing member is tightly fitted to the outer surface of the resin joint, thereby positioning the reinforcing member on the outside of the resin joint.

[0021] This simple method enables the creation of resin joints that are difficult to peel off from metal tubing.

[0022] Furthermore, the metal tube and the resin connector can be cylindrical. When the metal tube and the resin connector are cylindrical, during the pressing process, the resin connector can be pressed radially from its outer side towards the inner side of the end of the metal tube while the mounting portions of the metal tube and the resin connector are heated. In particular, when the metal tube and the resin connector are cylindrical with constant outer and inner diameters, during the pressing process, the resin connector can be pressed radially from its outer side towards the inner side of the metal tube while the mounting portions of the metal tube and the resin connector are heated.

[0023] When both the metal tube and the resin connector are cylindrical, by pressing the resin connector radially while the mounting portion of the metal tube and resin connector is heated, a structure can be obtained in which there is almost no gap between the resin connector and the roughened end of the metal tube, and the resin connector and the roughened end of the metal tube fit tightly together. This method is even more effective when both the metal tube and the resin connector are cylindrical with a constant outer diameter and a constant inner diameter.

[0024] When both the metal tube and the resin connector are cylindrical, it is preferable that the reinforcing member is also cylindrical. In this case, the outer circumferential surface of the resin connector is covered by the reinforcing member throughout the circumferential direction, thus achieving a structure in which the resin connector is less likely to peel off from the metal tube. The effects of the invention

[0025] The above method provides a manufacturing method for a pipe with a resin-made joint that provides high sealing performance. Attached Figure Description

[0026] Figure 1This is a front view of an example of a pipe with a resin fitting and other pipes. Figure 2 This is a cross-sectional view of an example of a pipe with a resin fitting and other pipes. Figure 3 This diagram illustrates the pretreatment process of the manufacturing method of the pipe with resin fittings according to the first embodiment. Figure 4 This is a diagram showing the pretreatment process after the manufacturing method of the pipe with resin fitting according to the first embodiment. Figure 5 This diagram illustrates the first installation step of the manufacturing method of the pipe with a resin connector according to the first embodiment. Figure 6 This diagram illustrates the heating process in the manufacturing method of the tube with a resin fitting according to the first embodiment. Figure 7 This diagram illustrates the pressing process of the manufacturing method of the tube with a resin connector according to the first embodiment. Figure 8 This diagram illustrates the cooling process of the manufacturing method of the pipe with a resin connector according to the first embodiment. Figure 9 This is a diagram showing the cooling process after manufacturing the pipe with resin fitting according to the first embodiment. Figure 10 This diagram illustrates the second assembly step of the manufacturing method of the pipe with resin fitting according to the first embodiment. Figure 11 This is a diagram showing the cooling process after manufacturing the pipe with resin fitting according to the second embodiment. Figure 12 This is a diagram illustrating the second installation step of the manufacturing method of the pipe with resin fitting according to the second embodiment. Figure 13 This is a diagram showing the pretreatment process after the manufacturing method of the pipe with resin joint according to the third embodiment. Figure 14 This diagram illustrates the heating process in the manufacturing method of the tube with a resin connector according to the third embodiment. Figure 15 This diagram illustrates the pressing process of the manufacturing method of the tube with a resin connector according to the third embodiment. Figure 16 This is a diagram showing the cooling process after manufacturing the pipe with resin fitting according to the third embodiment. Figure 17 This diagram illustrates the second installation step of the manufacturing method of the pipe with a resin connector according to the third embodiment. Detailed Implementation

[0027] [First Implementation] Figure 1 The diagram shows the connection between pipe 1 with a resin fitting and other pipes 2. Pipes 1 and 2 with resin fittings are used, for example, as vehicle hoses. Examples of vehicle hoses include air conditioning hoses and fuel hoses.

[0028] like Figure 1 and Figure 2 As shown, the pipe 1 with the resin fitting has a metal pipe 11, a resin fitting 12, and a reinforcing member 13. Figure 2 As shown, metal tube 11 is connected to tube 2. Resin connector 12 connects metal tube 11 and tube 2. Tube 2 is, for example, a resin tube.

[0029] The metal tube 11 is cylindrical. For example, the metal tube 11 can be cylindrical or square. Figure 1 The metal tube 11 shown is curved, but the shape of the metal tube 11 can be changed.

[0030] A "cylindrical" component refers to a component with a hole extending along the axial direction. This axially extending hole can have the same shape from one end to the other, or it can have a portion of the hole with a different shape from the rest. Similarly, a "cylindrical" component can have the same outer and inner diameter from one end to the other, or it can have a portion of the hole with a different outer and / or inner shape from the rest. For example, a "cylindrical" component can have the same outer diameter from one end to the other, or the same inner diameter from one end to the other, or a portion of the hole with a different outer diameter from the rest, or a portion of the hole with a different inner diameter from the rest.

[0031] The metal tube 11 is made of metal. Examples of materials for the metal tube 11 include iron, copper, copper alloys, aluminum, aluminum alloys, magnesium, magnesium alloys, or stainless steel, but it is not limited to these.

[0032] like Figure 2 As shown, the resin connector 12 is cylindrical. The definition of "cylindrical" is the same as that described in the description of the metal tube 11. The resin connector 12 can be, for example, cylindrical or square. When the metal tube 11 is cylindrical, the resin connector 12 is cylindrical. When the metal tube 11 is square, the resin connector 12 is square.

[0033] The resin connector 12 can be made of materials such as thermoplastic resins or elastomers. Examples of thermoplastic resins include polyamide (PA), polyethylene (PE), polypropylene (PP), polystyrene (PS), acrylonitrile / styrene resin (AS), acrylonitrile / butadiene / styrene resin (ABS), methacrylic acid resin (PMMA), and polyvinyl chloride (PVC). Examples of elastomers include thermoplastic elastomers. The resin connector 12 may contain fillers, flame retardants, and other additives.

[0034] like Figure 2 As shown, Figure 1 and Figure 2 The reinforcing member 13 shown is cylindrical. The definition of "cylindrical" is the same as that described in the metal tube 11. The reinforcing member 13 can be, for example, cylindrical or square. When the resin connector 12 is cylindrical, the reinforcing member 13 is cylindrical. When the resin connector 12 is square, the reinforcing member 13 is square.

[0035] The coefficient of linear expansion of the reinforcing member 13 is smaller than that of the resin connector 12. The coefficient of linear expansion is sometimes referred to as the coefficient of thermal expansion. The material of the reinforcing member 13 is not particularly limited as long as its coefficient of linear expansion is smaller than that of the resin connector 12. The material of the reinforcing member 13 can be, for example, metal, thermoplastic resin, thermosetting resin, or an elastomer. For example, when the reinforcing member 13 is made of metal, its coefficient of linear expansion is smaller than that of the resin connector 12. Examples of metals include those used in metal pipes 11. The material of the reinforcing member 13 can also be thermoplastic resin, thermosetting resin, or an elastomer, as long as its coefficient of linear expansion is smaller than that of the resin connector 12.

[0036] Next, the manufacturing method of pipe 1 with resin fittings will be described. It should be noted that... Figure 1 In the process, the pipe 2 is connected to the resin connector 12, but the connection between the pipe 2 and the resin connector 12 can be carried out before manufacturing the pipe 1 with the resin connector, during manufacturing the pipe 1 with the resin connector, or after manufacturing the pipe 1 with the resin connector. The following describes the case where, after manufacturing the pipe 1 with the resin connector, the pipe 2 is connected to the resin connector 12.

[0037] [Pretreatment process] like Figure 3As shown, a metal tube 11 is prepared. The outer surface of the end 11E of the metal tube 11 is roughened. The roughening treatment can be performed using known roughening methods. For example, roughening can be performed by laser processing, grinding, sandblasting, cutting, rolling, or knurling.

[0038] Figure 4 The roughened metal tube 11 is shown. The outer surface of the end 11E of the metal tube 11 is irregular. The roughness of the end 11E of the roughened metal tube 11 is not particularly limited. For example, the surface roughness Rz can be approximately 100 μm. Rz refers to the maximum height roughness. The maximum height roughness (Rz) is the sum of the height of the highest peak (Rp) and the depth of the lowest valley (Rv) of the roughened end 11E.

[0039] [First Installation Step] exist Figure 4 A resin connector 12 is mounted on the outer surface of the end 11E of the metal tube 11 shown. Figure 5 The diagram shows a resin connector 12 installed at the end 11E of a metal tube 11. With the resin connector 12 installed at the end 11E of the metal tube 11, a portion or all of the resin connector 12 is located on the outer side of the end 11E of the metal tube 11. In other words, a portion or all of the end 11E of the metal tube 11 is located on the inner side of the resin connector 12. With the resin connector 12 installed at the end 11E of the metal tube 11, a gap exists between the outer surface of the end 11E and the inner surface of the resin connector 12.

[0040] [Heating Process] With the resin connector 12 installed at the end 11E of the metal tube 11, the mounting portions of the metal tube 11 and the resin connector 12 are heated. "The mounting portions of the metal tube 11 and the resin connector 12" refer to "the portion of the metal tube 11 opposite the resin connector 12" and "the portion of the resin connector 12 opposite the metal tube 11." "The portion of the metal tube 11 opposite the resin connector 12" refers to "the outer surface of the end 11E of the metal tube 11 and its vicinity." "The portion of the resin connector 12 opposite the metal tube 11" refers to "the inner surface of the metal tube 11 opposite the end 11E and its vicinity within the resin connector 12."

[0041] There is no particular limitation on the method for heating the mounting portion of the metal tube 11 and the resin connector 12. For example, such as Figure 6As shown, in the metal tube 11, a heating device heats the portion away from the end 11E. Heat is transferred from the heated portion to the end 11E of the metal tube 11, thereby heating the end 11E of the metal tube 11. Heat is then transferred from the end 11E of the metal tube 11 to the inner surface and periphery of the resin connector 12 opposite to the end 11E. As a result, the mounting portion of the metal tube 11 and the resin connector 12 is heated.

[0042] There are no particular limitations on the heating method and heating device. General heating methods and devices can be used. The heating device can be, for example, a heater, a burner, or a high-frequency induction heating device.

[0043] "Heating the mounting portion of the metal tube 11 and the resin connector 12" includes not only the case of directly heating the mounting portion of the metal tube 11 and the resin connector 12 using a heating device, but also the case of heating the mounting portion of the metal tube 11 and the resin connector 12 by heating a portion different from the mounting portion, as described above, that is, the case of directly heating the mounting portion of the metal tube 11 and the resin connector 12 without using a heating device.

[0044] By heating the mounting portion of the metal tube 11 and the resin connector 12, the inner surface of the resin connector 12 opposite to the metal tube 11 and its surrounding area reach a temperature above the melting point or softening point of the resin connector 12, thereby melting or softening.

[0045] It should be noted that when heating the mounting portion of the metal tube 11 and the resin connector 12, it is preferable to heat the outer surface and periphery of the resin connector 12, as well as the portion of the resin connector 12 that is connected to the metal tube 11. Figure 2 The portions of the other tubes 2 shown are not heated, or even if heated, the heating temperature is below the softening point of the resin connector 12. Therefore, the outer surface of the resin connector 12, as well as the portions within the resin connector 12, can be kept warm. Figure 2 The other sections connected to tube 2 shown remain in the same shape as before heating. For example, as Figure 6 As shown, in the metal tube 11, by heating the portion away from the end 11E, it is possible to heat the mounting portion of the metal tube 11 and the resin connector 12 while suppressing heat on the outer surface and periphery of the resin connector 12, as well as the portion of the resin connector 12 that is connected to the metal tube 11. Figure 2 Heating of the portion connected to the other tube 2 shown.

[0046] [Pressing process] With the mounting portion of the metal tube 11 and the resin connector 12 heated, the resin connector 12 is pressed from its outer side toward the inner side of the end 11E of the metal tube 11. "The mounting portion of the metal tube 11 and the resin connector 12 is heated" means that the inner surface of the resin connector 12 opposite the metal tube 11 and its surrounding area are heated to a temperature higher than the melting point or softening point of the resin connector 12. During the heating process, since the mounting portion of the metal tube 11 and the resin connector 12 is heated, the resin connector 12 is pressed from its outer side toward the inner side of the end 11E of the metal tube 11. Thus, as... Figure 7 As shown, the portion of the resin connector 12 that faces the metal tube 11 enters a recess on the outer surface of the end 11E of the metal tube 11. Furthermore, this results in a state where there is almost no gap between the resin connector 12 and the end 11E of the metal tube 11. With almost no gap between the resin connector 12 and the end 11E of the metal tube 11, the resin connector 12 and the metal tube 11 are tightly fitted together.

[0047] [Cooling Process] After the pressing process, the resin connector 12 is cooled. For example, as... Figure 8 As shown, cooling gas can flow inside the metal tube 11. According to this method, firstly, the metal tube 11 is cooled. Cooling heat is transferred from the cooled metal tube 11 to the portion of the resin connector 12 opposite to the metal tube 11, thereby cooling the portion of the resin connector 12 opposite to the metal tube 11. As a result, the resin connector 12 solidifies in the recessed state of the end 11E of the metal tube 11. The resin connector 12 solidifies in a state where there is almost no gap between the resin connector 12 and the end 11E of the metal tube 11, and the resin connector 12 is tightly fitted to the metal tube 11.

[0048] Cooling methods are not limited to those described above. For example, the resin joint 12 can be cooled by blowing cold air from the outside of the resin joint 12. Alternatively, the resin joint 12 can be cooled to ambient temperature by allowing the metal tube 11 and the resin joint 12 to stand still.

[0049] [Second Installation Step] After the cooling process, the reinforcing component 13 is installed onto the resin connector 12. The installation method is not particularly limited. For example, making... Figure 9 The cylindrical reinforcing member 13, as shown, is located on the outside of the resin joint 12. Preferably, the resin joint 12 and the reinforcing member 13 are tightly fitted together with almost no gap between them. For example, as... Figure 10As shown, the reinforcing member 13 is pressed against the resin connector 12 from the outside. Thus, the resin connector 12 and the reinforcing member 13 fit tightly together with almost no gap between them. With the reinforcing member 13 installed on the resin connector 12, it will not detach from the resin connector 12.

[0050] Using the above method, pipe 1 with a resin-made joint can be obtained. By... Figure 2 The tube 2 shown is connected to the resin connector 12, resulting in a structure where the metal tube 11 is connected to the tube 2. When the tube 2 is made of resin, the resin connector 12 can be connected to the tube 2, for example, by laser welding.

[0051] By using the above method to manufacture pipe 1 with resin joints, the following effects can be obtained.

[0052] like Figure 7 As shown, with the mounting portion of the metal tube 11 and the resin connector 12 heated, the resin connector 12 is pressed from the outside of the resin connector 12 toward the inside of the end 11E of the metal tube 11. As a result, the molten or softened resin connector 12 enters multiple recesses on the roughened outer surface of the end 11E of the metal tube 11, and the resin connector 12 and the end 11E of the metal tube 11 are tightly fitted together with almost no gap between them.

[0053] It should be noted that the above-described structure cannot be obtained if only the end 11E of the metal tube 11 and the mounting portion of the resin connector 12 are heated, without pressing the resin connector 12 while the mounting portion is heated. When only the mounting portion is heated, the molten or softened resin connector 12 will not penetrate into any of the multiple recesses on the outer surface of the end 11E of the metal tube 11. Even if the molten or softened resin connector 12 does penetrate the recesses, gaps will remain. Therefore, when only the end 11E of the metal tube 11 and the mounting portion of the resin connector 12 are heated, a state in which there is almost no gap between the resin connector 12 and the end 11E of the metal tube 11, and the resin connector 12 and the end 11E of the metal tube 11 are not tightly fitted together.

[0054] After pressing the resin connector 12, it is cooled. As a result, the resin connector 12 cures, with almost no gap between it and the end 11E of the metal tube 11, and the resin connector 12 and the end 11E of the metal tube 11 are tightly fitted together. In this state, after the resin connector 12 has cured, the reinforcing member 13 is installed on it. In this state, the reinforcing member 13 is not installed on the resin connector 12 before it has cured.

[0055] Therefore, even when the resin joint 12 expands during high-temperature use of the pipe 1 with the resin fitting, and then contracts as the temperature decreases, almost no gap is generated between the resin joint 12 and the reinforcing member 13. Furthermore, since the linear expansion coefficient of the reinforcing member 13 is smaller than that of the resin joint 12, the outward expansion of the resin joint 12 at high temperatures is suppressed by the reinforcing member 13. Therefore, almost no gap is generated between the resin joint 12 and the reinforcing member 13. Consequently, almost no gap is generated between the resin joint 12 and the metal pipe 11. Therefore, even if the resin joint 12 softens at high temperatures, it is possible to prevent the resin joint 12 from peeling off from the metal pipe 11. Therefore, leakage of fluid flowing within the metal pipe 11 from between the metal pipe 11 and the resin joint 12 can be suppressed.

[0056] Furthermore, as demonstrated by the experiments described later, even under the harsh conditions of high-pressure fluid flowing in the metal tube 11 at high temperature, leakage of the fluid flowing in the metal tube 11 from between the metal tube 11 and the resin joint 12 can be suppressed.

[0057] As described above, according to the method of this embodiment, it is possible to manufacture a pipe 1 with a resin joint that provides a higher level of sealing between the metal pipe 11 and the resin joint 12 than in the past.

[0058] In addition, such as Figure 10 As shown, by simply pressing the reinforcing member 13 against the resin connector 12, the reinforcing member 13 and the resin connector 12 can be tightly fitted together, so that there is almost no gap between the reinforcing member 13 and the resin connector 12. This simple method allows for the formation of a structure in which the resin connector 12 is not easily detached from the metal tube 11.

[0059] In addition, the fluid flowing in the metal tube 11 is easily drawn from... Figure 10 The tip of end 11E of the metal tube 11 shown flows between the metal tube 11 and the resin connector 12. Therefore, the resin connector 12 is most easily peeled off near the tip of end 11E of the metal tube 11. However, as... Figure 10As shown, a resin connector 12 and a reinforcing member 13 are present on the outer side of the end 11E of the metal tube 11 and in the vicinity of it. Therefore, the resin connector 12 is not easily detached from the metal tube 11 at the end 11E of the metal tube 11 and in the vicinity of it.

[0060] Furthermore, since the reinforcing member 13 is cylindrical, its outer surface covers the resin connector 12. The reinforcing member 13 is present throughout the entire circumferential direction on the outer surface of the resin connector 12. This further improves the sealing performance between the metal tube 11 and the resin connector 12. Additionally, while the resin connector 12 is easily peeled off at and near the tip of the metal tube 11's end 11E, the reinforcing member 13 is present throughout the entire circumferential direction. Therefore, even in areas where the resin connector 12 is easily peeled off, it is not easily detached from the metal tube 11.

[0061] Alternatively, the metal tube 11 and the resin connector 12 can also be cylindrical. When the metal tube 11 and the resin connector 12 are cylindrical, during the pressing process, the resin connector 12 can be pressed radially while the mounting portions of the metal tube 11 and the resin connector 12 are heated. This results in a structure where there is almost no gap between the resin connector 12 and the end 11E of the metal tube 11, and the resin connector 12 and the end 11E of the metal tube 11 are tightly fitted. In particular, when the metal tube 11 and the resin connector 12 are cylindrical with a constant outer diameter and a constant inner diameter, pressing the resin connector 12 radially while the mounting portions of the metal tube 11 and the resin connector 12 are heated during the pressing process is effective in achieving the aforementioned effect.

[0062] When both the metal tube 11 and the resin connector 12 are cylindrical, it is preferable that the reinforcing member 13 is also cylindrical. In this case, since the outer circumferential surface of the resin connector 12 is covered by the reinforcing member 13 throughout the circumferential direction, the resin connector 12 becomes less likely to peel off from the metal tube 11.

[0063] [Second Implementation] Next, refer to the following Figure 11 and Figure 12 A method for manufacturing a pipe with a resin-coated joint according to a second embodiment of the present invention will be described. The main difference between the second embodiment and the first embodiment lies in the second installation step. It should be noted that descriptions of steps identical to those in the first embodiment are appropriately omitted. Furthermore, the same reference numerals are used for structures identical to those in the first embodiment, and their descriptions are appropriately omitted.

[0064] The pretreatment process, the first installation process, the heating process, and the cooling process are the same as those in the first embodiment. Figure 11 The metal tube 11, resin connector 12, and reinforcing member 213 after the cooling process are shown. Here, the case where the metal tube 11 and resin connector 12 are cylindrical will be described.

[0065] The reinforcing member 213 is a cylindrical component. The reinforcing member 213 can be either square or cylindrical. Here, the case where the reinforcing member 213 is cylindrical will be described. The front end of the reinforcing member 213 is convex inwards. The inner diameter of the portion of the reinforcing member 213 other than the front end is less than or equal to the outer diameter of the resin connector 12.

[0066] [Second Installation Step] like Figure 12 As shown, the portion opposite to the front end of the reinforcing member 213 is positioned opposite the resin connector 12, and the reinforcing member 213 is pressed axially into the resin connector 12 so that the reinforcing member 213 is positioned on the outside of the resin connector 12. Furthermore, the reinforcing member 213 is installed on the resin connector 12 by positioning it by hooking the front end of the reinforcing member 213 onto one end of the resin connector 12. Since the inner diameter of the portion of the reinforcing member 213 other than the front end is less than the outer diameter of the resin connector 12, the resin connector 12 and the reinforcing member 213 fit tightly together with almost no gap between them. With the reinforcing member 213 installed on the resin connector 12, the reinforcing member 213 will not detach from the resin connector 12.

[0067] Using the method described above, the second embodiment, like the first embodiment, can also produce a pipe with a high sealing performance and a resin joint. Furthermore, by simply pressing a reinforcing member 213 with an inner diameter less than the outer diameter of the resin joint 12 axially into the resin joint 12, a structure in which the resin joint 12 is less likely to peel off from the metal pipe 11 can be obtained.

[0068] [Third Implementation Method] Next, refer to the following Figures 13 to 17 A method for manufacturing a pipe with a resin-coated joint according to a third embodiment of the present invention will be described. The main difference between the third embodiment and the first embodiment lies in the second installation step. It should be noted that descriptions of steps identical to those in the first embodiment are appropriately omitted. Furthermore, the same reference numerals are used for structures identical to those in the first embodiment, and their descriptions are appropriately omitted.

[0069] The pretreatment process is the same as that in the first embodiment. Figure 13 The metal tube 11 and resin connector 312 after the pretreatment process are shown.

[0070] like Figure 13 As shown, the resin connector 312 has a tapered portion whose outer diameter increases towards one end near the axial direction. A metal tube 11 is disposed inside the tapered portion of the resin connector 312. Here, the case where the metal tube 11 is a cylinder with a constant outer and inner diameter will be described. In addition, the case where the resin connector 312 is a cylinder with a constant inner diameter and an outer diameter that varies along the axial direction will be described.

[0071] The first installation step, heating step, pressing step, and cooling step described below are the same as those in the first embodiment. These steps will be briefly described below.

[0072] [First Installation Step] A resin connector 312 is installed at the end 11E of the metal tube 11. Figure 14 The image shows the resin connector 312 installed at the end 11E of the metal tube 11. (As shown) Figure 14 As shown, in the axial direction of the metal tube 11, the outer surface of the tapered portion of the resin connector 312 increases as it moves away from the end 11E of the metal tube 11.

[0073] [Heating Process] With the resin connector 312 installed at the end 11E of the metal tube 11, as follows: Figure 14 As shown, the mounting portion of the metal tube 11 and the resin connector 312 is heated.

[0074] [Pressing process] With the mounting portion of the metal tube 11 and the resin connector 312 heated, the resin connector 312 is pressed from the outside of the resin connector 312 toward the inside of the end 11E of the metal tube 11. When pressing the resin connector 312, as follows... Figure 15 As shown, the resin connector 312 is pressed to maintain the shape of its tapered outer surface. By pressing the resin connector 312, the resin connector 312 and the metal tube 11 are tightly fitted together with almost no gap between them.

[0075] [Cooling Process] After the pressing process, the resin connector 312 is cooled.

[0076] Figure 16The metal tube 11, resin connector 312, and reinforcing member 313 after the cooling process are shown. The reinforcing member 313 is a cylindrical component. The inner surface of the reinforcing member 313 is tapered, with the inner diameter increasing towards one end in the axial direction. Here, the case where the reinforcing member 313 is cylindrical with an inner diameter varying along the axial direction will be explained.

[0077] [Second Installation Step] like Figure 16 As shown, in the axial direction of the resin connector 312, the direction in which the outer diameter of the resin connector 312 increases is the same as the direction in which the inner diameter of the reinforcing member 313 increases. From this state, the reinforcing member 313 is pressed into the resin connector 312 so that the reinforcing member 313 is positioned on the outside of the resin connector 312. The inner surface of the reinforcing member 313 is pressed against the outer surface of the resin connector 312, so that the resin connector 312 and the reinforcing member 313 fit tightly together with almost no gap between them. With the reinforcing member 313 installed in the resin connector 312, the reinforcing member 313 will not fall off the resin connector 312.

[0078] Using the method described above, the third embodiment, like the first embodiment, can also produce a pipe with a high sealing performance and a resin joint. Furthermore, by simply pressing the reinforcing member 313 into the resin joint 312, a structure can be obtained in which the resin joint 312 is less likely to peel off from the metal pipe 11. Example

[0079] The present invention will be described in more detail below through embodiments. However, the following embodiments do not limit the present invention, and any modifications or implementations made without departing from the spirit of this specification are included within the technical scope of the present invention.

[0080] (experiment) A tube with a resin-coated fitting was manufactured using the manufacturing method for the tube with a resin-coated fitting described in the first embodiment. Furthermore, a tube with a resin-coated fitting was manufactured by modifying a portion of the method described in the first embodiment. Table 1 and the following show the test conditions and results.

[0081] Aluminum tubing was used as the metal tubing. Polyamide 66 tubing was used as the resin connector. The first embodiment was used as the reinforcing component. Figure 9 and Figure 10 The reinforcing member is shown in the diagram. An aluminum reinforcing member was used as the reinforcing member.

[0082] As shown in Table 1, pretreatment was performed on the metal tubes in No. 2, No. 4, and No. 6. In this pretreatment process, the outer surface of the ends of the metal tubes was roughened using laser processing. The surface roughness Rz of the roughened outer surface of the ends of the metal tubes was approximately 100 μm. No. 1, No. 3, and No. 5 did not undergo any pretreatment process.

[0083] As shown in Table 1, in No. 1 and No. 2, no reinforcing member is installed on the resin joint. In No. 3 to No. 6, a reinforcing member is installed on the resin joint, but the timing of the installation differs. In No. 3 and No. 4, as described in the first embodiment, the reinforcing member is installed on the resin joint after the cooling process. In No. 5 and No. 6, while performing the heating process, the reinforcing member is positioned on the outside of the resin joint, and the reinforcing member is pressed from the outside, thereby pressing the resin joint against the metal tube. Thus, in No. 5 and No. 6, the heating process, the pressing process, and the second installation process are performed simultaneously. Then, the resin joint is cooled.

[0084] In the heating process, such as Figure 6 As shown, in a metal tube, a heating device is used to heat the portion away from the end, thereby heating the mounting portion of the metal tube and the resin connector. In the cooling process, such as Figure 8 As shown, the resin joint is cooled by allowing cooling gas to flow inside the metal tube.

[0085] After manufacturing pipes No.1 to No.6 with resin fittings, test samples were made with other pipes connected to each pipe with resin fittings, and the following tests were performed.

[0086] (Pressure resistance test) Under normal temperature conditions, gas was sealed into the test sample, and the pressure inside the test sample was set to 3.53 MPa for 5 minutes. Then, water at a pressure of 5.30 MPa was sealed into the test sample. In Table 1, cases with no leakage are marked as "○", and cases with leakage are marked as "×". Hereinafter, "leakage" will sometimes be abbreviated as "leakage".

[0087] (High temperature and repeated pressure test) Simulating harsh conditions inside a vehicle, test oil was sealed into a test sample at 140°C, and the sample was repeatedly pressurized from 0 MPa to 3.53 MPa. This pressurization was repeated 150,000 times. In Table 1, cases with no oil leakage are marked as "○", and cases with oil leakage are marked as "×". Hereinafter, "oil leakage" will sometimes be abbreviated as "leakage".

[0088] [Table 1]

[0089] The following information can be obtained from Table 1.

[0090] In Units No. 1, No. 3, and No. 5, which did not undergo a pretreatment process for the metal tubing, leaks occurred during the pressure test and the high-temperature repeated pressure test. In Units No. 3 and No. 5, the tubing with resin fittings was manufactured using the same method as in the first embodiment, except for the pretreatment process; however, leaks still occurred during the pressure test and the high-temperature repeated pressure test. As can be seen from the above, without a pretreatment process for the metal tubing, the resin fittings peel off from the metal tubing.

[0091] In No. 1 and No. 2, where the resin joint was not fitted with a reinforcing member, leakage occurred during repeated high-temperature pressure tests. In No. 2, the pipe with the resin joint was manufactured using the same method as in the first embodiment, except that a reinforcing member was not installed, but leakage still occurred during repeated high-temperature pressure tests. Therefore, it can be seen that when the resin joint is not fitted with a reinforcing member, the resin joint peels off from the metal pipe.

[0092] In No. 3 to No. 6, a reinforcing member is installed on the resin joint. In No. 3 and No. 4, the reinforcing member is installed after the cooling process. In other words, in No. 3 and No. 4, the reinforcing member is installed on the resin joint after the resin joint is tightly fitted to the metal tube. Here, in No. 3, as mentioned above, because the metal tube was not pretreated, leakage occurred during the pressure test and the high-temperature repeated pressure test. In No. 4, no leakage occurred during the pressure test and the high-temperature repeated pressure test. On the other hand, in No. 5 and No. 6, a second installation process of installing the reinforcing member is performed during the heating process of heating the resin joint and the pressing process of pressing the resin joint, followed by a cooling process of cooling the resin joint. In other words, in No. 5 and No. 6, the reinforcing member is installed on the resin joint during the process of tightly fitting the resin joint to the metal tube. Similar to No. 3, No. 5 leaked during the pressure test and the high-temperature repeated pressure test because no pretreatment process was performed on the metal tubing. No. 6 also leaked during the high-temperature repeated pressure test.

[0093] As can be seen from No.3 to No.6, even if the end of the metal tube is roughened during pretreatment, the resin joint will peel off from the metal tube under severe high temperature conditions when the resin joint is tightly fitted to the end of the metal tube and the reinforcing component is installed on the resin joint. However, if the resin joint is tightly fitted to the metal tube and then cured in a tightly fitted state before the reinforcing component is installed on the resin joint, the resin joint will not peel off from the metal tube even under severe high temperature conditions.

[0094] As can be seen from the above, by performing a pretreatment process on the metal pipe, the resin joint is tightly fitted to the metal pipe, and the reinforcing component is installed on the resin joint. Even under harsh conditions at high temperatures, it is possible to manufacture a pipe with a high sealing performance between the metal pipe and the resin joint.

[0095] The embodiments of the present invention have been described above based on the accompanying drawings, but it should be understood that the specific structure is not limited to these embodiments. Furthermore, the scope of the present invention is not shown by the foregoing description, but by the claims, and includes all modifications within the meaning and scope equivalent to the claims.

[0096] For example, the reinforcing components (13, 213, 313) may or may not be cylindrical.

[0097] Furthermore, the method of heating the mounting portion of the metal tube (11) and the resin connector (12, 312) is not limited to... Figure 6 , Figure 14 The method shown.

[0098] Furthermore, the method of installing the reinforcing components (13, 213, 313) onto the resin joints (12, 312) is not limited to the methods described in the first, second, and third embodiments above.

[0099] Furthermore, in the second embodiment, such as Figure 12 As shown, the front end of the reinforcing member 213 is positioned by attaching it to one end of the resin connector 12. However, the structure for positioning the reinforcing member 213 in the resin connector 12 is not limited to the above structure and can be modified. For example, a recess may be formed between one end and the other end of the resin connector 12 in the axial direction, and an inwardly oriented protrusion may exist between one end and the other end of the reinforcing member 213. The protrusion of the reinforcing member 213 is inserted into the recess of the resin connector 12, thereby positioning the reinforcing member by attaching it to the resin connector.

[0100] In addition, in the second embodiment, after the reinforcing member 213 is pressed into the resin joint 12 for positioning, the reinforcing member 213 can be pressed against the resin joint 12.

[0101] Furthermore, in the third embodiment, the metal tube 11, resin connector 312, and reinforcing member 313 are described as being cylindrical, but they can also be cylindrical. Additionally, in the first and second embodiments, the metal tube 11, resin connector 12, and reinforcing members (13, 213) can be either cylindrical or cylindrical.

[0102] As a viewpoint different from the above-described embodiments and modifications, instead of roughening the outer surface of the metal tube end, an adhesive can be applied to the outer surface of the metal tube end to manufacture a tube with a resin-based connector. For example, in the second embodiment, as... Figure 11 As shown, the end 11E of the metal tube 11 is roughened. However, in the pretreatment step of the second embodiment, by applying an adhesive to the end 11E of the metal tube 11 instead of roughening it, a tube with a resin connector can be manufactured. Similarly, in the third embodiment, by applying an adhesive to the end 11E of the metal tube 11 instead of roughening it, a tube with a resin connector can be manufactured. Explanation of reference numerals in the attached figures

[0103] 1: Pipe with resin fitting; 2: Pipe; 11: Metal pipe; 12, 312: Resin fitting; 13, 213, 313: Reinforcing components.

Claims

1. A method for manufacturing a pipe with a resin fitting, comprising a method for manufacturing a pipe with a resin fitting joined to a metal pipe, characterized in that, It includes the following processes: The pretreatment process roughens the outer surface of the end of the metal tube. The first installation step involves installing a cylindrical resin connector at the end of the roughened metal tube. In the heating process, while the resin connector is installed at the end of the metal tube, the mounting portion of the metal tube and the resin connector is heated. In the pressing process, while the mounting portion of the metal tube and the resin connector is heated, the resin connector is pressed from the outside of the resin connector toward the inside of the metal tube. The cooling process involves cooling the resin connector after pressing it against the inside of the metal tube; and In the second installation step, after the resin joint has cooled, a reinforcing member is installed on the outer surface of the resin joint, on the outside of the end of the metal tube. The coefficient of linear expansion of the reinforcing component is smaller than that of the resin joint.

2. The method for manufacturing a pipe with a resin-coated joint according to claim 1, characterized in that, In the heating process, The mounting portion of the metal tube and the resin connector is heated by heating the metal tube using a heating device.

3. The method for manufacturing a pipe with a resin-fitted joint according to claim 1 or 2, characterized in that, The reinforcing component is a cylindrical component.

4. The method for manufacturing a pipe with a resin-fitted joint according to claim 1 or 2, characterized in that, In the second installation process, Press the reinforcing member radially toward the resin joint so that the inner surface of the reinforcing member fits tightly against the outer surface of the resin joint.

5. The method for manufacturing a pipe with a resin-fitted joint according to claim 1 or 2, characterized in that, In the second installation process, The reinforcing member, having an inner diameter less than the outer diameter of the resin joint, is pressed axially into the resin joint so that the inner surface of the reinforcing member is in close contact with the outer surface of the resin joint, thereby positioning the reinforcing member on the outside of the resin joint.

6. The method for manufacturing a pipe with a resin-fitted joint according to claim 1 or 2, characterized in that, The outer surface of the resin joint has a tapered portion whose outer diameter increases towards one end near the axial direction. The reinforcing component is a cylindrical component. The inner surface of the reinforcing member has a tapered portion whose inner diameter increases as it approaches one end along the axial direction. In the second installation process, In the axial direction of the resin joint, the direction in which the outer diameter of the resin joint increases is the same as the direction in which the inner diameter of the reinforcing member increases, and the reinforcing member is pressed into the resin joint so that the inner surface of the reinforcing member is in close contact with the outer surface of the resin joint, so that the reinforcing member is positioned on the outside of the resin joint.

7. The method for manufacturing a pipe with a resin fitting according to claim 1 or 2, characterized in that, The metal tube and the resin connector are cylindrical. In the pressing process, while the mounting portion of the metal tube and the resin connector is heated, the resin connector is pressed radially from the outside of the resin connector toward the inside of the end of the metal tube.

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