Manufacturing method of pipe with fitting

Abstract

To provide a manufacturing method of a pipe with a joint capable of reducing the number of processes in comparison with a conventional method, and further reducing an outer diameter of a cylindrical portion of the joint in comparison with the conventional method.SOLUTION: In a state that a front face of a flare portion (13) formed on an end portion of a pipe (3) is kept into contact with a seal face (11) formed inside of a cylindrical portion (6) of a joint (2), the cylindrical portion (6) of a part to which a collar member (4) is inserted, is caulked from a radial outer part of the cylindrical portion (6) while pressing an end face of the collar member (4) to a rear face of the flare portion (13).SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a jointed pipe formed by connecting a pipe and a joint. [Background technology]

[0002] Patent Document 1 describes the following method for connecting a pipe and a joint: The pipe is inserted into the tubular portion of the joint. A jig is inserted between the pipe body of the pipe and the tubular portion of the joint. This jig is used to plastically deform a portion of the inner wall of the tubular portion, and the flared portion of the pipe is fixed to the inner surface of the tubular portion. The jig is then removed, and an elastic member (e.g., a rubber tube) is placed between the tubular portion and the pipe body. With the elastic member placed, the tubular portion is crimped from the radially outward direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-204391 A Summary of the Invention [Problem to be solved by the invention]

[0004] The method described in Patent Document 1 involves a step of plastically deforming a part of the inner wall of the tubular part using a jig, and therefore involves a large number of steps. In addition, to plastically deform a part of the inner wall of the tubular part using a jig, the tubular part needs to be firmly supported from the side opposite to the side where the jig is inserted. This requires providing a shoulder on the outside of the tubular part to receive the force from the jig, which increases the outer diameter of the tubular part.

[0005] An object of the present invention is to provide a method for manufacturing a jointed pipe which requires fewer steps than before and which allows the outer diameter of the tubular portion of the joint to be smaller than before. [Means for solving the problem]

[0006] The manufacturing method of a pipe with a fitting disclosed in the present application is a manufacturing method of a pipe with a fitting by connecting a pipe and a fitting, and includes the following steps: a flare portion forming process for forming a flare portion at an end of the pipe, the flare portion having an outer diameter larger than that of the pipe main body of the pipe; a collar manufacturing process for manufacturing a tubular collar member to be inserted onto the pipe main body; a pipe / collar insertion process for inserting the end of the pipe on the side where the flare portion is formed and the collar member into the tubular portion of the fitting; and a crimping process for crimping the tubular portion of the portion where the collar member is inserted from the radially outside of the tubular portion while pressing the end face of the collar member against the rear face of the flare portion with the front face of the flare portion abutting against a sealing surface formed inside the tubular portion. Effect of the Invention

[0007] According to the above manufacturing method, the number of steps can be reduced compared to the conventional method, and the outer diameter of the tubular portion of the joint can be made smaller than the conventional method. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a side view of the fitting pipe of the first embodiment. [Diagram 2] 2 is a cross-sectional view taken along line AA in FIG. 1. [Diagram 3] 10 is a cross-sectional view illustrating a process of fitting a cylindrical collar member onto a pipe body of a pipe. FIG. [Figure 4] 10 is a cross-sectional view illustrating a process of inserting an end of a pipe and a collar member into a cylindrical portion of a joint. FIG. [Diagram 5] 4 is a cross-sectional view showing a state in which an end of a pipe and a collar member are inserted into a cylindrical portion of a joint. FIG. [Figure 6] FIG. 4 is a cross-sectional view of a fitting pipe according to a second embodiment. [Figure 7] FIG. 6 is a view corresponding to FIG. 5 and showing a joint-equipped pipe according to a second embodiment. [Figure 8] 3 is a photograph showing a cross section of a joint-equipped pipe having the structure shown in FIGS. 1 and 2 that was actually manufactured. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] An embodiment of the present invention will be described with reference to the drawings. In the following description, an embodiment is shown in which a joint called an eye joint is used as the joint 2 to be connected to a pipe 3. Note that the manufacturing method for a joint-equipped pipe of the present invention is not limited to a joint called an eye joint, and can be applied to various joints.

[0010] 1 and 2, the jointed pipe 1 includes a joint 2, a pipe 3, and a cylindrical collar member 4. The jointed pipe 1 is used for hydraulic piping and the like.

[0011] The joint 2 has an annular joint body 5 and a tubular portion 6 (socket portion) protruding from the side surface of the joint body 5. A bolt or the like is inserted into a hole 5a in the joint body 5. A hole 5b having a smaller diameter than the hole 5a is formed in the peripheral wall of the joint body 5. The holes 5a and 5b are perpendicular to each other and communicate with each other.

[0012] The tubular portion 6 has a first tubular portion 7 on the joint body 5 side and a second tubular portion 8 on the opposite side to the joint body 5 side. The first tubular portion 7 has a hole 9 extending in its axial direction. The hole 9 and the hole 5b of the joint body 5 are integrally molded. The hole 9 and the hole 5b are continuous holes and serve as a flow path for a fluid.

[0013] The second tubular portion 8 is formed with a hole 10 extending in its axial direction. The hole 10 is a hole that serves as a receiving port for the pipe 3, and is a hole into which the pipe 3 and the collar member 4 are inserted. The hole 10 has a larger diameter than the hole 9. The center of the hole 10 is the same as the center of the hole 9, and the holes 10 and 9 extend in the same axial direction. When the pipe 3 is inserted into the hole 10, the hole 9 and the pipe 3 communicate with each other. Note that the hole 10 shown in Figures 1 and 2 is the hole after crimping, and the hole 10 before crimping is shown in Figures 4 and 5. The diameter of the hole 10 before crimping is approximately the same as the outer diameter of the collar member 4.

[0014] 4, 5, etc., an annular recess is formed at the boundary (step) between holes 10 and 9, recessing toward the first cylindrical section 7. The surface of this recess on the hole center side is the sealing surface 11 with which the flared section 13 of the pipe 3 abuts. The sealing surface 11 is tapered from the first cylindrical section 7 side toward the second cylindrical section 8 side, that is, it is a tapered annular surface tapered toward the side where the pipe 3 is inserted.

[0015] The pipe 3 has a cylindrical pipe body 12 and a flare portion 13. The flare portion 13 is formed at the end of the pipe 3. The outer diameter of the flare portion 13 is larger than the outer diameter of the pipe body 12. The flare portion 13 has a ring shape that widens at the tip. The outer diameter of the flare portion 13 is approximately the same as the outer diameter of the collar member 4.

[0016] The collar member 4 has a tapered surface 4a at its axial tip as shown in Fig. 3, for example. The tapered surface 4a is an annular inclined surface that widens toward the tip. The tapered surface 4a has a shape that conforms to the rear surface of the flare portion 13 of the pipe 3. The rear surface of the flare portion 13 is the surface of the flare portion 13 on the pipe main body portion 12 side in the axial direction of the pipe 3. The front surface of the flare portion 13 is the surface opposite to the rear surface in the axial direction of the pipe 3.

[0017] 5, the collar member 4 is manufactured to a length such that a part of the collar member 4 protrudes from the tubular portion 6 of the joint 2. A collar member 4 having an inner diameter approximately equal to the outer diameter of the pipe main body 12 is used.

[0018] In this embodiment, the collar member 4 is a metallic collar member, that is, a metallic collar. The material of the collar member 4 is, for example, iron (metallic material). The material of the collar member 4 is not limited to iron, and may be a metallic material other than iron, such as stainless steel, brass, or copper. The material of the joint 2 and the pipe 3 is also, for example, iron (metallic material). The material of the joint 2 and the pipe 3 is also not limited to iron, and may be a metallic material other than iron, such as stainless steel, brass, or copper. In addition, the collar member 4, the joint 2, and the pipe 3 may be plated or resin coated.

[0019] The collar member 4 may be made of a material other than metal, such as rubber or resin.

[0020] A method for manufacturing the jointed pipe 1 will now be described.

[0021] A flare portion 13 is formed at the end of the pipe 3 (flare portion forming step), and the pipe 3 as shown in the cross section in FIG. 3 is prepared. A metallic cylindrical member (not shown) is cut to a length that allows a portion of the member to protrude from the cylindrical portion 6 of the joint 2, and a cylindrical collar member 4 is prepared (collar manufacturing step). At this time, the axial end face of the collar member 4 is tapered to have a shape that conforms to the rear surface of the flare portion 13 of the pipe 3, in this embodiment, a tapered surface 4a that flares out at the tip (collar processing step). Note that the end face processing (tapering) of the collar member 4 is not essential.

[0022] Next, as shown in Fig. 3, the collar member 4 is fitted onto the pipe body 12 of the pipe 3 from the side where the flare portion 13 is not formed. The collar member 4 is fitted onto the pipe body 12 from the tapered surface 4a side. Then, as shown in Fig. 4, the end of the pipe 3 on the side where the flare portion 13 is formed and the collar member 4 fitted onto the pipe body 12 are inserted into the second tubular portion 8 of the joint 2 that is separately manufactured and prepared (pipe collar insertion process).

[0023] After the above-mentioned pipe / collar insertion process is performed, the three components, the fitting 2, the pipe 3, and the collar member 4, are in the state shown in Figure 5. The front surface of the flare portion 13 of the pipe 3 abuts against the seal surface 11 formed inside the cylindrical portion 6 of the fitting 2, and the tapered surface 4a of the collar member 4 abuts against the rear surface of the flare portion 13.

[0024] It should be noted that it is not necessarily necessary to insert the end of the pipe 3 and the collar member 4 into the second tubular portion 8 of the joint 2 in a state in which the collar member 4 is fitted onto the pipe main body 12 of the pipe 3, i.e., in a state in which the collar member 4 is set onto the end of the pipe 3. After the end of the pipe 3 is inserted alone into the second tubular portion 8 of the joint 2, the collar member 4 may be fitted onto the pipe main body 12 and the collar member 4 may be inserted into the second tubular portion 8.

[0025] Next, with the front surface of the flare portion 13 of the pipe 3 abutting against the seal surface 11 formed inside the cylindrical portion 6 of the joint 2, the second cylindrical portion 8 of the joint 2, which is the portion into which the collar member 4 is inserted, is crimped from the radial outside of the cylindrical portion 6 while pressing the tapered surface 4a of the collar member 4 against the rear surface of the flare portion 13 (crimping process). The crimping direction of the second cylindrical portion 8 is indicated by an arrow in FIG. 2. The crimping method may be eight-way crimping, which crimps the crimped portion from eight sides, or hexagonal crimping, which crimps the crimped portion from six sides. Note that the method is not limited to eight-way crimping or hexagonal crimping, and the second cylindrical portion 8 may be crimped from multiple directions on the radial outside of the cylindrical portion 6.

[0026] The method of pressing the tapered surface 4a of the collar member 4 against the rear surface of the flare portion 13 is, for example, as follows. A coil spring (not shown) is inserted around the pipe main body 12, and the collar member 4 is pressed axially into the second cylindrical portion 8 by this coil spring. Alternatively, the collar member 4 is pressed axially into the second cylindrical portion 8 by using an air cylinder or the like. The force pressing the collar member 4 axially into the second cylindrical portion 8 is not large (a large force is not required). Therefore, the force pressing the collar member 4 axially into the second cylindrical portion 8 can be received by supporting the joint main body 5 against some kind of jig.

[0027] When the second tubular portion 8 of the joint 2, into which the collar member 4 is inserted, is crimped from the radially outer side of the tubular portion 6, the collar member 4, together with the second tubular portion 8 and the pipe main body 12, is partially recessed (plastically deformed) radially inward. The collar member 4 also stretches (plastically deforms) slightly in its axial direction. The collar member 4 is sandwiched between the second tubular portion 8 and the pipe main body 12, so it is easy to stretch in the axial direction.

[0028] When plastic deformation extending in the axial direction occurs in the collar member 4, the end face of the collar member 4 (the tapered face 4a in this embodiment) strongly presses the rear face of the flare portion 13 of the pipe 3. As a result, the front face of the flare portion 13 is strongly pressed against the seal face 11 formed inside the cylindrical portion 6, and the sealing property between the fitting 2 and the pipe 3 is ensured. In addition, by crimping from the radially outward direction, a part of the second cylindrical portion 8 located on the rear side of the flare portion 13 is slightly recessed radially inward, and the collar member 4 is pressed against the outer circumferential face of the pipe main body 12, and the second cylindrical portion 8 is pressed against the outer circumferential face of the collar member 4. As a result, the front face of the flare portion 13 is kept strongly pressed against the seal face 11, and the pipe 3 will not come out of the fitting 2 unless a very large tensile force is applied. Figure 8 is a photograph of the actually manufactured fitting-equipped pipe 1 having the structure shown in Figures 1 and 2. The manufactured fitting-equipped pipe 1 was cut in half in the axial direction and photographed. As can be seen from FIG. 8, the front surface of the flare portion 13 of the pipe 3 is securely pressed against the seal surface 11 inside the joint 2, and this state is maintained.

[0029] (effect) It is possible to stretch (plastically deform) the collar member 4 in its axial direction by crimping the second tubular portion 8 of the fitting 2, into which the collar member 4 is inserted, from the radially outer side of the tubular portion 6 without specifically pressing the end face of the collar member 4 against the rear surface of the flare portion 13 of the pipe 3. However, in this case, the collar member 4 may move in a direction that causes it to come out of the second tubular portion 8. Therefore, it is difficult to achieve a state in which the front surface of the flare portion 13 is strongly pressed against the seal surface 11, and it is difficult to ensure sealing between the fitting 2 and the pipe 3.

[0030] In contrast, in the above manufacturing method, the second tubular portion 8 of the joint 2, which is the portion into which the collar member 4 is inserted, is crimped from the radially outer side of the tubular portion 6 while pressing the end face of the collar member 4 (the tapered surface 4a in this embodiment) against the rear surface of the flare portion 13 of the pipe 3. The crimping is performed in a short time, and the force acting on the outer circumferential surface of the second tubular portion 8 is similar to an impact force. Therefore, by crimping the second tubular portion 8 from the radially outer side while pressing the end face of the collar member 4 against the rear surface of the flare portion 13, it is possible to prevent the collar member 4 from moving in the direction of coming out of the second tubular portion 8, and to make the front surface of the flare portion 13 be strongly pressed against the seal surface 11.

[0031] In addition, in the above manufacturing method, there is no step of plastically deforming a part of the inner wall of the cylindrical portion 6 using a jig as in Patent Document 1 (JP Patent Publication No. 2020-204391). Therefore, there is no step of removing the jig from the cylindrical portion 6. Therefore, according to the above manufacturing method, the number of steps can be reduced compared to the conventional method. In addition, since there is no need to provide a shoulder portion on the cylindrical portion 6 to receive the force from the jig as in Patent Document 1, the outer diameter of the cylindrical portion 6 can be reduced accordingly.

[0032] In the above manufacturing method, in the pipe / collar insertion step, after the collar member 4 is extrapolated onto the pipe main body 12, the end of the pipe 3 on the side where the flared portion 13 is formed and the collar member 4 are inserted into the second tubular portion 8 (tubular portion 6) of the joint 2. This makes it easier to insert the pipe 3 and the collar member 4 into the tubular portion 6 than when the end of the pipe 3 is inserted alone into the second tubular portion 8 (tubular portion 6) of the joint 2 and then the collar member 4 is inserted into the second tubular portion 8 (tubular portion 6).

[0033] Furthermore, by machining the end face of the collar member 4 into a shape that conforms to the rear surface of the flare portion 13 (tapered surface 4a in this embodiment), the contact area between the end face of the collar member 4 and the rear surface of the flare portion 13 can be increased, and the flare portion 13 can be more reliably pressed against the seal surface 11 by crimping. Also, the end of the collar member 4 and the flare portion 13 become integrated.

[0034] Furthermore, by manufacturing the collar member 4 to a length that allows a portion of the collar member 4 to protrude from the tubular portion 6 of the fitting 2, it becomes easier to press the end face of the collar member 4 against the rear surface of the flare portion 13 when performing the crimping process.

[0035] In this embodiment, a metal collar is used as the collar member 4. With this configuration, the front surface of the flare portion 13 can be pressed against the seal surface 11 more strongly than when a collar member 4 made of rubber or resin is used.

[0036] Fig. 6 is a cross-sectional view of a fitting pipe 201 of the second embodiment. Fig. 7 is a cross-sectional view showing the state of the fitting pipe 201 before the crimping process. For the fitting pipe 201 of the second embodiment, the same members and parts as those constituting the fitting pipe 1 of the first embodiment are given the same reference numerals as those constituting the fitting pipe 1 of the first embodiment.

[0037] The difference between the jointed pipe 1 of the first embodiment and the jointed pipe 201 of the second embodiment is the structure around the flared portion of the pipe 3.

[0038] The outer diameter of the flare portion 14 of the pipe 3 constituting the jointed pipe 201 of the second embodiment is larger than the outer diameter of the pipe body 12. The flare portion 14 has a tapered ring shape. The outer diameter of the flare portion 14 is approximately the same as the outer diameter of the collar member 4.

[0039] The seal surface 15 formed at the boundary (step) between the holes 10 and 9 in the tubular portion 6 is a tapered annular surface that widens from the first tubular portion 7 side toward the second tubular portion 8 side in accordance with the shape of the front surface of the flared portion 14, that is, that widens toward the side into which the pipe 3 is inserted. The flared portion 14 of the pipe 3 abuts against this seal surface 15.

[0040] The end face 4b of the collar member 4 that contacts the rear surface of the flare portion 14 of the pipe 3 is rounded at its inner corners along the entire circumference so that the end face 4b fits the rear surface of the flare portion 14 of the pipe 3. As in the first embodiment, it is not essential to perform the end face processing of the collar member 4. In the second embodiment, the above-mentioned rounded chamfering is not essential.

[0041] A manufacturing method for the jointed pipe 201 of the second embodiment is similar to the manufacturing method for the jointed pipe 1 of the first embodiment, and therefore a description thereof will be omitted.

[0042] The present invention is not limited to the above-described embodiments, and it is possible to combine elements of the above-described embodiments as appropriate and to make various modifications to the above-described embodiments without departing from the spirit of the present invention.

[0043] For example, the above embodiment can be modified as follows.

[0044] The collar member 4 does not have to be formed to a length that causes a portion of the collar member 4 to protrude from the tubular portion 6 of the joint 2. In other words, the collar member 4 may be formed to a length that causes the end face of the tubular portion 6 and the collar end face to be flush with each other when inserted into the tubular portion 6, or may be formed to a length that causes the entire collar member 4 to fit inside the tubular portion 6 (second tubular portion 8). [Explanation of symbols]

[0045] 1, 201: Pipe with fitting 2: Joint 3: Pipe 4: Colored parts 4a: Tapered surface (end face) 4b: End face 6: Cylindrical part 11, 15: Sealing surface 12: Pipe body 13, 14: Flare section

Claims

1. A method for manufacturing a pipe with a fitting by connecting a pipe and a fitting, comprising the steps of: a flare portion forming step of forming a flare portion having an outer diameter larger than that of a pipe body portion of the pipe at an end portion of the pipe; a collar manufacturing process for manufacturing a cylindrical collar member to be fitted onto the pipe main body; a pipe / collar insertion process for inserting the end of the pipe on the side where the flare portion is formed and the collar member into a cylindrical portion of the joint; a crimping process for crimping the cylindrical portion, at a portion into which the collar member is inserted, from a radially outer side of the cylindrical portion while pressing an end face of the collar member against a rear face of the flare portion in a state in which the front face of the flare portion is abutted against a seal surface formed inside the cylindrical portion; Equipped with The collar member is a metallic collar. A method for manufacturing pipes with fittings.

2. The method for manufacturing a jointed pipe according to claim 1, In the pipe-collar insertion step, the collar member is fitted onto the pipe body, and then the end of the pipe on the side where the flare portion is formed and the collar member are inserted into the tubular portion of the joint. A method for manufacturing pipes with fittings.

3. In the method for manufacturing a jointed pipe according to claim 1 or 2, The method further includes a collar processing step performed before the pipe collar insertion step, in which the end surface of the collar member is processed into a shape that conforms to the rear surface of the flare portion. A method for manufacturing pipes with fittings.

4. In the method for manufacturing a jointed pipe according to any one of claims 1 to 3, In the collar manufacturing step, the collar member is manufactured to a length such that a portion of the collar member protrudes from the cylindrical portion of the joint. A method for manufacturing pipes with fittings.

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