Pipe end deformation jig and pipe fitting installation method using the same

Abstract

To provide a pipe end deforming tool that makes it difficult for a pipe end portion to come off in an inserted state of the pipe end portion into a pipe accommodation recess of a pipe fitting.SOLUTION: A pipe end deforming tool 30 comprises: a base 31; and a pair of protrusions 40 each protrudes from a front surface 33 of the base 31 and faces each other spaced apart from each other. Opposing surfaces 41 of the pair of protrusions 40 are inclined so as to approach each other toward the base 31. A cross section of the pipe end portion 14 is deformed by inserting the plastic-deformable pipe end portion 14 between the pair of protrusions 40 of the pipe end deforming tool 30. Thereafter, the pipe end portion 14 is inserted into a pipe accommodation recess 24 of the pipe fitting 20.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a jig for deforming a pipe end and a method for attaching a pipe fitting to a pipe end using the jig, and more particularly to a pipe end deforming jig and a pipe fitting attachment method used when fitting a plastically deformable pipe end into an annular pipe receiving recess of a pipe fitting. [Background technology]

[0002] For example, a polyethylene three-layer pipe that includes a metal layer such as aluminum as an intermediate layer is known as an air conditioning pipe for air conditioning equipment (see Patent Document 1, etc.). When extending this type of pipe, a pipe fitting is attached to the pipe end. For example, the pipe fitting of Patent Document 2 has a compression ring fitted around the outer periphery of a cylindrical fitting body. An annular pipe accommodating recess is formed between the fitting body and the compression ring. The pipe end is inserted into the pipe accommodating recess, and the compression ring is compressed from the outer periphery and crimped and deformed, thereby connecting the pipe end to the pipe fitting. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Publication number 3-041184 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-325904 Summary of the Invention [Problem to be solved by the invention]

[0004] When connecting the aforementioned pipe end and pipe joint, after the pipe end is inserted into the pipe accommodating recess of the pipe joint, there is a possibility that the pipe joint may come off the pipe end and fall during the period until the compression ring is crimped and deformed, and there is room for improvement from the viewpoint of safety. SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a method for making it difficult for a pipe end portion to come off when inserted into a pipe receiving recess of a pipe joint, and a tool that can be used for this method. [Means for solving the problem]

[0005] In order to achieve the above object, the present invention provides a pipe end deformation jig for deforming a cross section of a plastically deformable pipe end, comprising: With the base, a pair of projections projecting from the front surface of the base and spaced apart from each other and facing each other; The opposing surfaces of the pair of projections are inclined so as to approach each other toward the base.

[0006] The tube end is inserted between the pair of protrusions of the tube end deformation jig, thereby deforming the cross section of the tube end, i.e., reducing the diameter of the tube end in the opposing direction of the protrusions and expanding the diameter of the tube end in the width direction perpendicular to the opposing direction and along the front surface. A pipe fitting having an annular pipe receiving recess is prepared separately, and the cross-sectionally deformed pipe end is inserted into the pipe receiving recess. This allows the inner circumferential portions of the pipe end on both sides in the diameter-reducing direction to be pressed against the inner circumferential wall of the pipe receiving recess, or the outer circumferential portions of the pipe end on both sides in the diameter-expanding direction to be pressed against the inner circumferential wall of the pipe receiving recess. As a result, the pipe fitting before crimping can be prevented from falling off the pipe end. Preferably, the tube end deforming jig has a higher rigidity than the tube end, and more preferably, the tube end deforming jig is made of metal, which allows the cross section of the tube end to be reliably plastically deformed.

[0007] Preferably, each of the pair of opposing surfaces has an arc shape when viewed from a direction facing the front side surface, and includes an inclined arc concave surface having the inclination, whereby the cross section of the tube end can be deformed into an elliptical shape by inserting the tube end between the pair of opposing surfaces.

[0008] Preferably, the radius of curvature of the inclined arc concave surface is larger than the outer radius of the tube end before deformation, thereby making it possible to make the radius of curvature of the side portion of the tube end that presses against the pair of opposing surfaces larger than before cross-sectional deformation, and to deform the tube end into an elliptical cross section so that the opposing direction of the pair of opposing surfaces is the minor axis direction of the tube end after cross-sectional deformation. More preferably, the center of curvature of the inclined arc-shaped concave surface is positioned closer to the other protrusion than the midpoint between the pair of protrusions, thereby ensuring that the radius of curvature of the inclined arc-shaped concave surface is larger than the outer radius of the tube end before deformation. More preferably, the inclined arc-shaped concave surface is a partially cylindrical concave surface whose axis is inclined with respect to a direction perpendicular to the opposing direction of the protrusions and the width direction of the protrusions, thereby making it possible to make the radius of curvature of the inclined arc-shaped concave surface constant in the height direction of the protrusions and facilitating the production of the inclined arc-shaped concave surface. The inclined arc concave surface may be a partially tapered surface whose radius of curvature changes along the height direction of the protrusion.The arc of the inclined arc concave surface may be an ellipse.

[0009] Preferably, the distance between the widthwise central portions of the inclined arcuate concave surfaces of the pair of opposing surfaces is equal to or greater than the outer diameter of the tube end before deformation at the height of the tip of the protrusion in the protruding direction, and is smaller than the outer diameter of the tube end before deformation at the height near the front side surface. This allows the tube end to be easily inserted between the pair of protrusions, and allows the cross-sectional deformation of the tube end to occur as it is inserted deeper between the pair of protrusions.

[0010] Preferably, an opening that allows the tube end to expand in diameter is formed between the edges of the pair of protrusions on the same side in the width direction, thereby allowing the tube end to expand in diameter in the width direction and deform into an elliptical cross section so that the width direction corresponds to the major axis direction of the tube end after cross-sectional deformation.

[0011] The method of the present invention is a method for attaching a pipe fitting having an annular pipe receiving recess to a plastically deformable pipe end using the pipe end deforming jig, comprising the steps of: The tube end is inserted between the pair of protrusions of the tube end deformation jig, thereby reducing the diameter of the tube end in the opposing direction of the protrusions, and expanding the diameter of the tube end in a width direction perpendicular to the opposing direction and along the front side surface, Thereafter, the tube end is inserted into the tube receiving recess. According to this method, the cross section of the pipe end can be reliably deformed using the pipe end deforming jig. Then, by inserting the cross section-deformed pipe end into the pipe receiving recess of the pipe fitting, the pipe end presses against the inner wall on the outer or inner circumference of the pipe receiving recess, generating frictional resistance. This prevents the pipe fitting from falling off the pipe end before crimping.

[0012] Preferably, the diameter reduction and diameter expansion cause the inner diameter of the pipe end in the diameter reduction direction to be equal to or smaller than the inner diameter of the pipe accommodating recess, or the outer diameter of the pipe end in the diameter expansion direction to be equal to or larger than the outer diameter of the pipe accommodating recess. This ensures that the cross-sectionally deformed pipe end is pressed against the inner wall on the outer or inner side of the pipe accommodating recess, and reliably prevents the pipe fitting from falling off the pipe end before crimping. [Effects of the Invention]

[0013] According to the present invention, the pipe end portion can be made less likely to come off when inserted into the pipe accommodating recess portion of the pipe joint. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a plan view of a pipe end deforming jig according to a first embodiment of the present invention. [Figure 2(a)] FIG. 2(a) is a front view of the tube end deforming jig taken along line IIa-IIa in FIG. [Figure 2(b)] FIG. 2(b) is a side cross-sectional view of the tube end deforming jig taken along line IIb-IIb in FIG. 2(a). [Figure 3] FIG. 3 is a perspective view of the tube end deforming jig. [Figure 4]Fig. 4(a) is a cross-sectional view showing how the tube end is deformed by the tube end deforming jig, and Fig. 4(b) is a cross-sectional view showing the tube end after being deformed by the tube end deforming jig. [Figure 5] FIG. 5 is a plan cross-sectional view taken along line VV in FIG. 4(b). [Figure 6] Fig. 6(a) is a partially cutaway side view showing the deformed pipe end portion fitted into the pipe joint and before crimping, and Fig. 6(b) is a cross-sectional view taken along line VIb-VIb in Fig. 6(a). [Figure 7] Figures 7(a) to 7(f) show other embodiments (modified examples) of the tube end deforming jig, where Figure 7(a) is a plan view of the second embodiment, Figure 7(b) is a cross-sectional view along line VIIb-VIIb in Figure 7(a), Figure 7(c) is a plan view of the third embodiment, Figure 7(d) is a cross-sectional view along line VIId-VIId in Figure 7(c), Figure 7(e) is a plan view of the fourth embodiment, and Figure 7(f) is a cross-sectional view along line VIIf-VIIf in Figure 7(e). DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The pipe end deforming jig according to this embodiment is used, for example, in the piping installation of air conditioning pipes in a building, in a pre-process when the air conditioning pipes are connected to pipe joints.

[0016] <Air conditioning pipe 10> As shown in Figure 4(a), the air conditioning pipe 10 is made of a three-layer pipe with an intermediate layer 12 made of a metal such as aluminum interposed between an inner layer 11 and an outer layer 13 made of a resin such as polyethylene (PE). The inclusion of the metal intermediate layer 12 allows the air conditioning pipe 10 to be plastically deformable.

[0017] <Pipe fitting 20> As shown in FIG. 6(a), the pipe fitting 20 has a cylindrical fitting body 21, and an annular pipe accommodating recess 24 formed between the fitting body 21 and a compressible ring 22, which is fitted onto the outer periphery of one end side (the right side in FIG. 6(a)). As shown in FIGS. 6(a) and 6(b), the pipe end 14 of the air conditioning pipe 10 is inserted into the pipe accommodating recess 24 to be connected to the pipe fitting 20. A threaded portion 23 is formed on the end of the fitting body 21 opposite the compressible ring 22. As shown by the two-dot chain line in FIG. 6(a), the threaded portion 23 is connected to the pipe 10A to be connected.

[0018] <Tube end deformation jig 30> Fig. 1 shows a pipe end deforming jig 30 according to this embodiment. The pipe end deforming jig 30 is used to deform the cross section of the pipe end 14 of the air conditioning pipe 10 (Figs. 4(a) and 4(b)) prior to connecting the air conditioning pipe 10 to a pipe joint 20 (Fig. 6).

[0019] As shown in Figures 2(a) and 2(b), the tube end deforming jig 30 includes a base 31 and a pair of protrusions 40. As shown in Figure 1, the base 31 is formed in a generally circular plate shape. One or more holes 32 are formed in the base 31. These holes 32 are used to attach a burr removal drive unit and to remove burrs when removing burrs from the tube end 14. In other words, the tube end deforming jig 30 also serves as a tube end mounting member for a burr removal device. In other words, the tube end mounting member for a burr removal device is given the function of the tube end deforming jig. From the viewpoint of deforming the tube end 14, the hole 32 may be omitted, and the tube end deforming jig 30 may be a dedicated jig for deforming the tube end.

[0020] As shown in Fig. 3, a pair of protrusions 40 are provided on the base 31. These protrusions 40 protrude from the front side surface 33 of the base 31 and face each other at a distance in one direction along the front side surface 33 (the up-down direction in Fig. 1). Hereinafter, this one direction will be referred to as the "facing direction" or "protrusion facing direction." A direction perpendicular to the protrusion facing direction and along the front side surface 33 (the left-right direction in Fig. 1) will be referred to as the "width direction." A direction perpendicular to the protrusion facing direction and the width direction (the direction perpendicular to the paper surface in Fig. 1) will be referred to as the "protrusion height direction" or "direction facing the front side surface 33."

[0021] As shown in FIG. 1, each protrusion 40 has a generally arc-shaped (fan-shaped) shape when viewed from the direction facing the front side surface 33. As shown in FIGS. 1 and 2(b), the opposing surfaces 41 of a pair of protrusions 40 are arc-shaped concave surfaces and are slightly inclined so as to approach each other as they approach the base 31. That is, each of the opposing surfaces 41 of a pair of protrusions 40 includes an inclined arc-shaped concave surface 42 that is arc-shaped when viewed from the direction facing the front side surface 33 and is inclined as described above. A tip end 42a of the inclined arc-shaped concave surface 42 in the protrusion protruding direction is connected to the top end surface 43 of the protrusion 40 via a rounded corner portion 45. A base end 42b of the inclined arc-shaped concave surface 42 reaches the front side surface 33.

[0022] The inclined arc concave surface 42 constitutes a part (partial cylindrical concave surface) of an imaginary cylindrical surface C40 shown by a dashed line in Fig. 1. As shown in Fig. 2(b), an axis L40 of the imaginary cylindrical surface C40 is slightly inclined with respect to a central axis L31 of the base 31 that is aligned in the projection height direction. In the drawing, only the cylindrical surface C40 and its axis L40 that corresponds to the inclined arcuate concave surface 42 on one side (upper side in FIG. 1) of the pair of opposing surfaces 41 is shown.

[0023] The radius of curvature r42 (FIG. 1) of the inclined arc-shaped concave surface 42 is constant in the projection height direction. The radius of curvature r42 of the inclined arc-shaped concave surface 42 is greater than the outer radius r14 of the pipe end portion 14 before deformation, which is indicated by the two-dot chain line in FIG. 1. As shown in FIG. 1, the center of curvature C42 of the inclined arc-shaped concave surface 42 is positioned offset toward the opposing projection 40 (e.g., the lower side in FIG. 1) from the midpoint between the pair of projections 40, i.e., from the central axis L31 of the base 31.

[0024] 4(a), the distance D42a between the center portions in the width direction at the tip ends 42a (tip height in the protrusion protrusion direction) of the pair of inclined arcuate concave surfaces 42 is equal to or greater than the outer diameter φ14 (= 2 × r14) of the tube end portion 14 before deformation (D42a ≧ φ14). Preferably, the distance D42a is approximately 101% to 102% of the outer diameter φ14 (D42a = φ14 × 1.01 to φ14 × 1.02).

[0025] 4(a), the distance D42b between the center portions in the width direction at the base ends 42b (at the height near the front side surface 33) of the pair of inclined arcuate concave surfaces 42 is smaller than the outer diameter φ14 before deformation of the tube end portion 14 (D42b<φ14). Preferably, the distance D42b is approximately 93% to 97% of the outer diameter φ14 (D42b=φ14×0.93 to φ14×0.97).

[0026] As shown in FIG. 1, an opening 34 is formed between the edge portions 44 of the pair of projections 40 on the same side in the width direction. A step 47 is formed between the base 31 and a back surface 46 of each projection 40 opposite the opposing surface 11 .

[0027] The pipe end deformation jig 30 is made of a metal such as steel or iron, and has higher rigidity than the pipe end 14 .

[0028] The pipe end deforming jig 30 is used as follows. As shown in Figure 4(a), the pipe end 14 is inserted between a pair of protrusions 40 of the pipe end deformation jig 30. At the tip 42a of the protrusion 40, D42a ≥ φ14, so the insertion operation can be easily performed. As shown in Figure 4(b), the tube end 14 is further inserted toward the base 31. At this time, both side portions 14a of the tube end 14 in the protrusion-facing direction come into contact with the opposing surfaces 41 of the pair of protrusions 40, and are pushed inward along the slopes of these opposing surfaces 41.

[0029] As a result, as shown in Figure 5, the tube end 14 is gradually reduced in diameter in the direction facing the protrusion and gradually expanded in the width direction. As a result, the cross section of the tube end 14 is deformed into an ellipse with the minor axis in the direction facing the protrusion and the major axis in the width direction. Moreover, the oblateness of the cross section increases toward the tip of the tube end 14. At the base end 42b of the projection 40, D42b<φ14, so that the diameter of the tube end 14 can be reliably reduced in the direction facing the projection. The opposing surface 41 of each protrusion 40 has a center of curvature C42 biased toward the opposing protrusion 40 and forms an arcuate concave surface 42 with r42>r14, so that both side portions 14a of the pipe end 14 in the protrusion opposing direction can be reliably flattened. Furthermore, the open portions 34 of the tube end deforming jig 30 can reliably allow the expansion of the diameter of both widthwise side portions 14b of the tube end portion 14.

[0030] Preferably, as shown in Figures 5 and 6(b), the cross section of the pipe end 14 is deformed so that the inner diameter φ14a on the short diameter side of the pipe end 14 is equal to or smaller than the inner diameter of the pipe accommodating recess 24 of the pipe fitting 20, i.e., equal to or smaller than the outer diameter φ21 of the fitting body 21 (φ14a ≦ φ21), or so that the outer diameter φ14b on the long diameter side of the pipe end 14 is equal to or larger than the outer diameter of the pipe accommodating recess 24, i.e., equal to or larger than the inner diameter φ22 of the compressed ring 22 (φ14b ≧ φ22).

[0031] The cross-sectional deformation of the tube end 14 causes plastic deformation of the aluminum intermediate layer 12 at the tube end 14. Therefore, the cross-sectional deformation of the tube end 14 is plastic deformation. Because the tube end deforming jig 30 has higher rigidity than the tube end 14, the tube end 14 can be reliably plastically deformed.

[0032] After the cross section of the tube end 14 is deformed by the tube end deforming jig 30, the tube end 14 is pulled out of the tube end deforming jig 30. Because the tube end 14 has been plastically deformed, the elliptical cross section is maintained even after it is released from the tube end deforming jig 30.

[0033] Next, as shown in Fig. 6(a), the pipe end portion 14 with its cross section deformed is inserted into the annular pipe accommodating recess 24 of the pipe fitting 20. Then, as shown in Fig. 6(b), the inner peripheral portions of both side portions 14a in the minor axis direction of the pipe end portion 14, which has an elliptical cross section of φ14a≦φ21 or φ14b ≧φ22, are pressed against the fitting body 21 (the inner wall on the inner peripheral side of the pipe accommodating recess 24). Alternatively, the outer peripheral portions of both side portions 14b in the major axis direction of the pipe end portion 14 are pressed against the compressed ring 22 (the inner wall on the outer peripheral side of the pipe accommodating recess 24). This creates frictional resistance between the pipe end portion 14 and the pipe fitting 20, making it difficult for the pipe end portion 14 to come out of the pipe receiving recess 24. As a result, it is possible to prevent the pipe fitting 20 from falling off the pipe end portion 14 before crimping, which will be described later. Thereafter, the compressed ring 22 is crimped by a crimping tool (not shown) so as to be compressed from the outer periphery, thereby connecting the pipe end portion 14 and the pipe joint 20 inseparably.

[0034] The inclined arc concave surface 42 of the tube end deforming jig 30 is a partially cylindrical concave surface with a constant radius of curvature r42 in the projection height direction, which makes it easy to manufacture the tube end deforming jig 30.

[0035] Next, another embodiment of the present invention will be described. In the following embodiment, the same components as those already described will be denoted by the same reference numerals in the drawings and the description thereof will be omitted. As shown in FIG. 7, the thickness, shape, etc. of the protrusion 40 can be set as appropriate. <Second embodiment (FIGS. 7(a) and 7(b))> 7(a) and 7(b), in a tube end deforming jig 30B according to the second embodiment of the present invention, the thickness of the protrusion 40 (the distance between the opposing surface 41 and the back surface 46) is greater than in the first embodiment, and the top end surface 43 of the protrusion 40 has a larger area than in the first embodiment. The back surface 46 of the protrusion 40 is continuous and flush with the outer peripheral surface of the base 31. According to the second embodiment of the tube end deformation jig 30B, even if the worker's hand hits the top end surface 43 during the cross-sectional deformation process of the tube end 14 (Figure 4), the top end surface 43 is flat, so the worker will not feel excessive pain.

[0036] <Third embodiment (FIGS. 7(c) to 7(d))> 7(c) and 7(d), in a tube end deforming jig 30C according to the third embodiment of the present invention, the thickness of the protrusions 40 is smaller than that of the tube end deforming jig 30B according to the second embodiment. The back surface 46 is flush with and continuous with the outer peripheral surface of the base 31.

[0037] <Fourth embodiment (FIGS. 7(e) to 7(f))> 7(e) and 7(f), in a tube end deforming jig 30D according to the fourth embodiment of the present invention, the thickness of the protrusions 40 is smaller than that of the tube end deforming jig 30C according to the third embodiment. The back surface 46 is flush with and continuous with the outer peripheral surface of the base 31.

[0038] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the invention. For example, the inclined arcuate concave surface 42 may be a partially tapered surface whose radius of curvature changes along the height direction of the protrusion 40. The arcuate shape of the inclined arcuate concave surface 42 in a plan view may be an ellipse. [Industrial Applicability]

[0039] The present invention can be applied to, for example, the installation of air conditioning pipes for air conditioning equipment in a building. [Explanation of symbols]

[0040] 10 Air conditioning equipment piping 11 Inner layer 12 Middle Class 13 Outer layer 14 Pipe end 14a Side of reduced diameter 14b Side of the expanded diameter 20 Pipe fittings 21 Joint body 22 Compressed Ring 24 Pipe receiving recess 30 Pipe end deformation jig 31 Base 33 Front side 34 Open area 40 protrusions 41 Opposite surface 42 Inclined circular concave surface 42a Tip 42b Proximal end 43 Apical surface 44 Edge 45 Corner section 46 Back

Claims

1. A pipe end deformation jig for deforming a cross section of a plastically deformable pipe end, With the base, a pair of projections projecting from the front surface of the base and spaced apart from each other and facing each other; a tube end deforming jig characterized in that the opposing surfaces of the pair of protrusions are inclined so as to approach each other as they approach the base, and each of the pair of opposing surfaces is arc-shaped when viewed from the direction facing the front side surface, and includes an inclined arc-shaped concave surface with the inclination.

2. 2. A tube end deforming jig according to claim 1, wherein the radius of curvature of the inclined arc concave surface is greater than the outer radius of the tube end before deformation.

3. 3. A pipe end deforming jig according to claim 1, wherein the center of curvature of the inclined arc concave surface is positioned offset toward the other protrusion from the midpoint between the pair of protrusions.

4. A tube end deformation jig as described in any one of claims 1 to 3, characterized in that the inclined arcuate concave surface is a partially cylindrical concave surface whose axis is inclined with respect to a direction perpendicular to the opposing direction of the protrusions and the width direction.

5. 5. A tube end deformation jig according to claim 1, wherein the distance between the widthwise central portions of the inclined arc concave surfaces of the pair of opposing surfaces is equal to or greater than the outer diameter of the tube end before deformation at a height near the tip of the protrusion in the protrusion direction, and is smaller than the outer diameter of the tube end before deformation at a height near the front side surface.

6. A tube end deformation jig as described in any one of claims 1 to 5, characterized in that an opening is formed between the edges of the pair of protrusions on the same side in the width direction, allowing the tube end to expand in diameter.

7. A method for fitting a pipe fitting having an annular pipe accommodating recess to a plastically deformable pipe end using a pipe end deformation tool that deforms the cross section of a plastically deformable pipe end, the pipe end deformation tool comprising a base and a pair of protrusions that protrude from the front surface of the base and are spaced apart and opposed to each other, the opposed surfaces of the pair of protrusions being inclined so as to approach each other as they approach the base, The tube end is inserted between the pair of protrusions of the tube end deformation jig, thereby reducing the diameter of the tube end in the opposing direction of the protrusions, and expanding the diameter of the tube end in a width direction perpendicular to the opposing direction and along the front side surface, and then inserting the pipe end into the pipe receiving recess.

8. 8. The pipe fitting installation method according to claim 7, characterized in that, due to the diameter reduction and diameter expansion, the inner diameter of the pipe end in the diameter reduction direction becomes equal to or smaller than the inner diameter of the pipe accommodating recess, or the outer diameter of the pipe end in the diameter expansion direction becomes equal to or larger than the outer diameter of the pipe accommodating recess.

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