Method and structure for connecting metal flexible tubes

Abstract

This invention provides a method and structure for connecting metal flexible tubes that prevents the cut surface of the blade from being exposed to the outside when crimped with a crimping ring, thereby avoiding damage to surrounding parts without compromising aesthetics, eliminating the need to trim the tip of the blade, and improving work efficiency. [Solution] When crimping the blade attached to the outer surface of the metal flexible tube 2 into the groove 12 of the connection portion 11 of the pipe member 1 using the crimping ring 3, the blade is first pinched and cut between one end face 13 of the groove 12 and one end face 31 of the crimping ring 3. Then, the pinched surface 24 is pushed down to the bottom surface 16 along the one end face 13 of the groove 12 as the crimping ring 3 continues to crimp.

Description

Technical Field

[0001] The present invention relates to a pipe joint for feeding a pressure fluid, and particularly to a connection method and a connection structure of a metal flexible tube having excellent flexibility.

Background Art

[0002] Generally, a pipe joint using a metal flexible tube is widely used for piping various fluids such as water supply because it has displacement absorption and high freedom in the piping direction. As this type of pipe joint, for example, as shown in Patent Document 1, a cylindrical pipe member having a connection portion on one end side and a blade that extends while being adhered to the outer surface side of the main body portion of the metal flexible tube and whose tip is connected to the outer surface side of the connection portion of the pipe member have been conventionally known (see Patent Document 1).

[0003] In this conventional product, the connection portion of the pipe member is provided with an annular first concave groove recessed over the entire circumferential direction on the end side closer to the main body portion side of the main body portion of the metal flexible tube, and an annular second concave groove recessed over the entire circumferential direction at a position closer to the main body portion side of the pipe member at a required interval from the first concave groove. An elastic seal member fitted in the first concave groove, and a caulking ring having a ridge that is adhered from above in a state where a blade is externally mounted on the connection portion of the pipe member and is fitted into the second concave groove, and having a flat circumferential surface that can be closely joined to a flat joint portion, is provided. When the blade is caulked by the caulking ring, the connection structure for the connection portion of the pipe member is provided by linking the caulking amount of the elastic seal member with the fitting depth of the ridge into the second concave groove.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, in such metal flexible tube connection structures, when crimping the crimping ring, the tip of the blade, which is fitted into a groove such as a second groove along with a rib, may protrude outward from inside the groove. In short, as shown in Figures 13 and 14, the tip of the blade c attached to the outer surface of the main body b of the metal flexible tube a may protrude outward from between one end face of the groove e, which is the base end of the connecting member d such as a pipe member, and one end face of the crimping ring f.

[0006] In that case, if the tip of blade c protrudes outward beyond the crimping ring f, it will not only significantly impair the aesthetic appearance but may also cause damage such as scratches to the surrounding parts of the crimping ring f.

[0007] Therefore, as shown in Figures 15 and 16, it is conceivable to cut off the tip of the blade c that protrudes outward from the crimping ring f using a cutter g positioned along one end face of the groove e.

[0008] However, even if the tip of blade c is cut off with cutter g, burrs remain on the cut surface h. Therefore, the burred cut surface h still protrudes outward from the crimping ring f, which detracts from the aesthetics and may cause damage such as scratches to the surrounding parts of the crimping ring f. Moreover, the process of cutting off the tip of blade c after crimping with the crimping ring f is required separately, which worsens work efficiency, so improvement was highly desired.

[0009] The present invention has been made in view of the above, and its purpose is to provide a method and structure for connecting a metal flexible tube that can reliably prevent damage to parts around the crimping ring without impairing aesthetics by preventing the cut surface of the blade from being exposed to the outside when crimped with a crimping ring, and can also improve work efficiency by eliminating the need to cut the tip of the blade. [Means for solving the problem]

[0010] To achieve the above objective, the present invention is based on a connection method in which a blade attached to the outer surface of the main body of a metal flexible tube is connected to a connection portion provided on the tip side of a cylindrical member to be connected. Furthermore, the connection portion of the member to be connected is provided with an annular groove recessed over the entire circumference in the axial direction of the connection portion, and a crimping ring that is crimped into the groove so that the blade is fitted into the connection portion of the member to be connected with the blade attached to the groove. Moreover, the inner diameter angle of one end face of the groove on the base end side of the member to be connected and the outer diameter angle of one end face of the crimping ring are set to angles such that when the crimping ring is crimped into the groove, only the tip side of the blade is clamped between the one end face of the groove and the one end face of the crimping ring. Furthermore, when crimping the crimping ring into the groove, the blade is positioned on the connection portion such that its tip is located on the base end side of the member to be connected, rather than on one end face of the groove, and only the tip of the blade positioned on the connection portion is clamped and cut by one end face of the crimping ring and one end face of the groove. Then, the clamped surface of the blade is pushed down to the bottom surface along one end face of the groove as the crimping ring is further crimped.

[0011] In contrast, to achieve the above objective, the present invention is based on a connection structure in which a blade attached to the outer surface of the main body of a metal flexible tube is connected to a connection portion provided on the tip side of a cylindrical member to be connected. The connection portion of the member to be connected is provided with an annular groove recessed over the entire circumferential direction at the axial midpoint of the connection portion, and a crimping ring that is crimped to fit the blade into the groove while it is attached to the connection portion of the member to be connected. Furthermore, the inner diameter angle of one end face of the groove, which is on the base end side of the member to be connected, and the outer diameter angle of one end face of the crimping ring are set to angles such that when the crimping ring is crimped to the groove, only the tip side of the blade, which is attached to the connection portion so that its tip is positioned on the base end side of the member to be connected, is clamped between the one end face of the groove and the one end face of the crimping ring. Furthermore, the cutting surface of the blade, which is clamped between one end face of the groove and one end face of the crimping ring, is pushed down to the bottom surface along the one end face of the groove as the crimping ring continues to crimp.

[0012] Furthermore, it is preferable to provide a gap greater than the thickness of the blade between the other end face of the crimping ring, which is the tip end of the member to be connected, and the other end face of the groove.

[0013] Furthermore, it is preferable to provide a chamfered portion on at least one of the outer end of the other end face of the groove and the inner end of the other end face of the crimping ring.

[0014] Furthermore, it is preferable to set the inner diameter angle of one end face of the groove and the outer diameter angle of one end face of the crimping ring to 90°, which is perpendicular to the axis of the member to be connected.

[0015] Furthermore, at least one of the bottom surface of the groove and the inner circumferential surface of the crimping ring may be provided with a surface that actively applies frictional force to the blade, which is pushed down to the bottom surface of the groove as the crimping ring is crimped. [Effects of the Invention]

[0016] In short, when a blade attached to the connection part of the member to be connected is crimped into the groove with a crimping ring, only the tip of the blade attached to the connection part is clamped and cut between one end face of the groove and one end face of the crimping ring, such that the tip is positioned on the base end side of the member to be connected, and the clamped surface (cut surface) of the blade is pushed down to the bottom surface along one end face of the groove as the crimping ring continues to crimp.

[0017] Therefore, when the blade tip is crimped by the crimping ring, the cut surface is not pushed down to the bottom of the groove and exposed to the outside as the crimping ring continues to crimp. As a result, the cut surface of the blade is hidden at the bottom of the groove, which does not detract from the aesthetics, and damage to the parts around the crimping ring is reliably prevented. Furthermore, the work of cutting the blade tip is eliminated, improving work efficiency.

[0018] Furthermore, a gap greater than the blade's thickness is provided between the other end face of the crimping ring and the other end face of the groove. This allows the base end of the blade to be smoothly guided out of the groove through the gap between the other end face of the groove and the other end face of the crimping ring when crimped by the crimping ring, thereby reliably preventing accidental cutting of the blade between the other end face of the groove and the other end face of the crimping ring when crimped by the crimping ring.

[0019] Furthermore, a chamfer is provided on at least one of the outer end of the other end face of the groove and the inner end of the other end face of the crimping ring. This allows the base end of the blade to be guided out of the groove more smoothly along the chamfer on at least one of the outer end of the other end face of the groove and the inner end of the other end face of the crimping ring when crimped with the crimping ring, thereby more reliably preventing accidental cutting of the blade between the other end face of the groove and the other end face of the crimping ring when crimped with the crimping ring.

[0020] Further, by setting the inner diameter angle of one side end face of the concave groove and the outer diameter angle of one side end face of the clamping ring to 90° perpendicular to the axis of the connection target member respectively, when clamping with the clamping ring, the pinching between one side end face of the concave groove and one side end face of the clamping ring can be surely performed with a simple structure.

[0021] Furthermore, at least one of the bottom surface of the concave groove and the inner peripheral surface of the clamping ring is provided with uneven portions that positively impart frictional force to the blade pushed into the bottom surface of the concave groove as the clamping ring is further clamped. Thereby, the frictional force acting on the blade when clamped by the clamping ring is effectively increased by the uneven portions provided on at least one of the bottom surface of the concave groove and the inner peripheral surface of the clamping ring, and the blade can be surely prevented from falling out of the concave groove when a load occurs.

Brief Description of the Drawings

[0022] [Figure 1] It is a cross-sectional view near the connection portion of the connection target member showing the state during clamping immediately after the blade is pinched by the clamping ring of the connection structure of the metal flexible tube according to the first embodiment of the present invention. [Figure 2] It is an enlarged cross-sectional view of the portion surrounded by the circle in FIG. 1. [Figure 3] It is a cross-sectional view near the connection portion of the connection target member showing the completed state of clamping the blade by the clamping ring in FIG. 1. [Figure 4] It is an enlarged cross-sectional view of the portion surrounded by the circle in FIG. 3. [Figure 5] It is an explanatory view showing the state before aligning the clamping ring for clamping the blade in the concave groove of the connection portion of the connection target member with a positioning device in the connection method using the connection structure of the metal flexible tube according to the second embodiment of the present invention with respect to the octagonal tightening machine. [Figure 6] It is an explanatory view showing the state where the clamping ring is completely aligned with the octagonal tightening machine by the positioning device in FIG. 5. [Figure 7]Figure 6 is an explanatory diagram showing the state after the alignment of the crimping ring has been crimped using an eight-way crimping machine. [Figure 8] Figure 7 is an explanatory diagram showing the state after the positioning device and the eight-way crimping machine have been detached from the crimped crimping ring. [Figure 9] Figure 8 is a cross-sectional view showing a state in which a cap nut, which is attached to the base end of a connecting member in which the blade has been crimped into the groove by the crimping ring, is fastened to the fixing pipe. [Figure 10] Figure 9 is an enlarged cross-sectional view of the area around the cap nut. [Figure 11] This figure, corresponding to Figure 2, shows the state during the crimping process immediately after the blade has been clamped and cut by the crimping ring of the connecting structure of a metal flexible tube according to a modified embodiment of the first embodiment. [Figure 12] Figure 11 is a diagram equivalent to Figure 4, showing the completed state of the blade crimping by the crimping ring. [Figure 13] This is a cross-sectional view of the vicinity of the connection portion of the connection target member, showing the completed crimping state of the blade by the crimping ring of a conventional metal flexible tube connection structure. [Figure 14] This is an enlarged cross-sectional view of the area circled in Figure 13. [Figure 15] Figure 13 is a cross-sectional view of the area near the connection point of the connecting member, showing the state after the crimping of the crimping ring is complete and the tip of the blade has been cut off with a cutter. [Figure 16] Figure 15 is an enlarged cross-sectional view of the area circled in the image. [Modes for carrying out the invention]

[0023] Hereinafter, embodiments of the present invention will be described based on the drawings.

[0024] Figure 1 is a cross-sectional view of the vicinity of the connection portion of the member to be connected, showing the state during crimping immediately after the blade has been clamped and cut by the crimping ring of the metal flexible tube connection structure according to the first embodiment of the present invention. Figure 2 is an enlarged cross-sectional view of the area circled in Figure 1. Figure 3 is a cross-sectional view of the vicinity of the connection portion of the member to be connected, showing the completed state of crimping of the blade by the crimping ring in Figure 1. Figure 4 is an enlarged cross-sectional view of the area circled in Figure 3.

[0025] As shown in Figures 1 to 4, a connecting portion 11 is provided at the tip (right end in Figures 1 to 4) of the cylindrical pipe member 1, which is the member to be connected. The pleated (corrugated) tip side (left end in Figures 1 to 4) of the main body portion 21 of the metal flexible tube 2 (hereinafter referred to as the flexible tube) is joined to the tip surface (right end surface in Figures 1 to 4) of this connecting portion 11 by welding.

[0026] Furthermore, a crimping ring 3 is attached to the outer circumference of the blade 23, and the connection structure of the flexible tube 2 is formed when the blade 23 is sandwiched and compressed between the pipe member 1 and the crimping ring 3.

[0027] The main body 21 of the flexible tube 2 is a hollow cylindrical structure made of a metal flexible tube, such as stainless steel, with a series of pleats (corrugations). The surface of this main body 21 is formed into a corrugated shape in cross-section by pleating a straight cylinder, and the inside and outside are constructed to maintain watertightness.

[0028] The blade 23 extends while attached to the outer surface of the main body 21 of the flexible tube 2, and its tip (the left end in Figures 1 to 4) is crimped and fixed by the crimping ring 3. The blade 23 is formed from blade units made of tape-shaped stainless steel plates or blade units made of wire strands arranged in a hollow cylindrical shape and connected together. The blade 23 is designed to protect against stretching of its uneven surface when pressure is applied from the inside, and a metal blade of any configuration may be used.

[0029] The pipe member 1 constitutes the connecting fitting portion of a pipe joint using a flexible tube 2, and the connecting portion 11 is formed on the outer circumference of the pipe member 1 with a flat surface of the same diameter and a wall thickness that is approximately twice as thick as the base end side. In the approximately middle (intermediate) part of the connecting portion 11 in the axial direction m, an annular groove 12 is provided that extends over the entire circumference of the connecting portion 11. This groove 12 is formed in a roughly U-shape in cross-section and its depth is set to approximately half the wall thickness of the connecting portion 11.

[0030] The crimping ring 3 is formed in a substantially rectangular cross-section that is long in the axial direction m of the pipe member 1. This crimping ring 3 is crimped from the outside so as to be fitted into the groove 12 with the blade 23 attached to the connecting part 11. The blade 23 is attached to the connecting part 11 so that when the crimping ring 3 is crimped, its tip is positioned on the base end side (left end side in Figures 1 to 4) of the pipe member 1, rather than on one end face 13 (left end face in Figures 1 to 4) of the groove 12.

[0031] The inner diameter angle of one end face 13 (left end face in Figures 1-4) of the groove 12 on the base end side of the pipe member 1, and the outer diameter angle of one end face 31 (left end face in Figures 1-4) of the crimping ring 3 are set at angles such that when the crimping ring 3 is crimped to the groove 12, only the tip side of the blade 23, whose tip is positioned on the base end side of the pipe member 1 beyond the one end face 13 of the groove 12, is clamped and cut between the one end face 13 of the groove 12 and the one end face 31 of the crimping ring 3. In other words, the inner diameter angle of one end face 13 of the groove 12 and the outer diameter angle of one end face 31 of the crimping ring 3 are angles at which the pipe member 1 is cut straight across with respect to the axis m of the pipe member 1, and are set to 90°, which is perpendicular to the axis m.

[0032] On the other hand, a gap S greater than the thickness of the blade 23 is provided between the other end face 32 (right end face in Figures 1 to 4) of the crimping ring 3, which is the tip end side of the pipe member 1 (right end side in Figures 1 to 4), and the other end face 14 (right end face in Figures 1 to 4) of the groove 12. Furthermore, chamfered portions 15 and 33, which are substantially parallel to each other, are provided at the outer end of the other end face 14 of the groove 12 and at the inner end of the other end face 32 of the crimping ring 3.

[0033] Then, when the crimping ring 3 is crimped with the one end face 13 of the groove 12 and the one end face 31 of the crimping ring 3 aligned in the direction of the axis m of the pipe member 1, the blade 23 is clamped and cut. In addition, the clamped surface 24 of the blade 23 that has been clamped and cut between the one end face 13 of the groove 12 and the one end face 31 of the crimping ring 3 is pushed down to the bottom surface 16 along the one end face 13 of the groove 12 as the crimping ring 3 is further crimped. In this case, the inner circumferential surface of the crimping ring 3 and the bottom surface 16 of the groove 12, which clamp the outer circumferential surface of the blade 23 from the inside and outside, are both formed as smooth surfaces without irregularities.

[0034] Next, we will describe an example of a connection method using the connection structure of the flexible tube 2.

[0035] This method for connecting the flexible tube 2 includes a moving device (not shown) that moves the pipe member 1 forward and backward in the axial direction m, and a crimping machine (not shown) that is provided radially outward of the pipe member 1 and crimps the crimping ring 3 from that radially outward position.

[0036] First, the tip of the blade 23 is attached to the connection portion 11 of the pipe member 1. At this time, the tip of the blade 23 is located closer to the base end of the pipe member 1 than one end face 13 of the groove 12 of the connection portion 11. Also, the crimping ring 3 is located closer to the main body portion 21 of the flexible tube 2 (to the right in Figures 1 to 4) than the groove 12.

[0037] Next, the pipe member 1 is moved forward toward the main body portion 21 of the flexible tube 2 by the moving device, and this forward movement of the pipe member 1 is stopped when one end face 13 of the groove 12 coincides with one end face 31 of the crimping ring 3 in the direction of the axis m of the pipe member 1.

[0038] Then, as shown in Figures 1 and 2, the crimping ring 3 is crimped from a radially outward position by a crimping machine so that it is fitted into the groove 12 via the blade 23. At this time, the blade 23 is clamped and cut by one end face 13 of the groove 12 and one end face 31 of the crimping ring 3.

[0039] Subsequently, as shown in Figures 3 and 4, as the crimping machine continues to crimp the crimping ring 3, the cutting surface 24 of the cut blade 23 is pushed down to the bottom surface 16 while aligned with one end surface 13 of the groove 12.

[0040] Subsequently, the crimping machine is detached radially outward from the crimping ring 3 to complete the crimping of the crimping ring 3, and the moving device is moved back toward the base end of the pipe member 1.

[0041] Therefore, in this embodiment, when the blade 23 attached to the connection portion 11 of the pipe member 1 is crimped to the groove 12 by the crimping ring 3, only the tip of the blade 23 attached to the connection portion 11 is clamped and cut between the one end surface 13 of the groove 12 and the one end surface 31 of the crimping ring 3, such that the tip is positioned on the base end side of the pipe member 1 than the one end surface 13 of the groove 12. The clamped surface 24 (cut surface) of the blade 23 is then pushed down to the bottom surface 16 along the one end surface 13 of the groove 12 as the crimping ring 3 continues to crimp.

[0042] Therefore, when the blade 23 is crimped by the crimping ring 3, the cutting surface 24 of the blade 23 is not pushed down to the bottom surface 16 of the groove 12 and exposed to the outside as the crimping ring 3 continues to crimp. This ensures that the cutting surface 24 (cut surface) of the blade 23 is hidden at the bottom surface 16 of the groove 12, without compromising aesthetics, and reliably prevents damage to parts around the crimping ring 3. Furthermore, it eliminates the need to cut the tip of the blade 23, thereby improving work efficiency.

[0043] Furthermore, a gap S greater than the thickness of the blade 23 is provided between one end face 32 of the crimping ring 3 and one end face 14 of the groove 12, and approximately parallel chamfered portions 15 and 33 are provided on the outer end of one end face 14 of the groove 12 and the inner end of one end face 32 of the crimping ring 3, respectively. As a result, when crimped by the crimping ring 3, the base end of the blade 23 is smoothly guided out from inside the groove 12 along the chamfered portions 15 and 33 on the outer end of the other end face 14 of the groove 12 and the inner end of the other end face 32 of the crimping ring 3, thereby reliably preventing accidental cutting of the blade 23 between the other end face 14 of the groove 12 and the other end face 32 of the crimping ring 3 when crimped by the crimping ring 3.

[0044] Furthermore, since the inner diameter angle of one end face 13 of the groove 12 and the outer diameter angle of one end face 31 of the crimping ring 3 are set to 90°, which is perpendicular to the axis m of the pipe member 1, the clamping and cutting between one end face 13 of the groove 12 and one end face 31 of the crimping ring 3 can be reliably performed with a simple configuration when crimped by the crimping ring 3.

[0045] Next, a second embodiment of the present invention will be described based on the drawings.

[0046] In this embodiment, the configurations of the member to be connected and the object to be crimped have been modified. Furthermore, the configurations of the device for moving the member to be connected axially and the crimping machine for crimping the crimping ring have also been modified. Note that the other configurations, excluding the member to be connected and the object to be crimped, are the same as in the first embodiment; therefore, the same reference numerals are used for the same parts, and their detailed descriptions are omitted.

[0047] Figure 5 is an explanatory diagram showing the state before the crimping ring, which crimps a blade into the groove of the connection portion of the member to be connected, is aligned with the eight-way crimping machine by the positioning device in a connection method using the flexible tube connection structure according to the second embodiment of the present invention. Figure 6 is an explanatory diagram showing the state after the crimping ring has been aligned with the eight-way crimping machine by the positioning device of Figure 5. Furthermore, Figure 7 is an explanatory diagram showing the state after the crimping ring aligned in Figure 6 has been crimped by the eight-way crimping machine, and Figure 8 is an explanatory diagram showing the state after the positioning device and the eight-way crimping machine have been detached from the crimped crimping ring in Figure 7.

[0048] In other words, in this embodiment, as shown in Figures 5 to 8, the crimping ring 9 that crimps the blade 23 is formed in a substantially rectangular cross-section that is long in the axial direction n of the cylindrical sleeve 5, which is the member to be connected. The sleeve 5 constitutes the connecting fitting portion of the pipe joint using the flexible tube 2, and a connecting portion 51 is provided on its outer surface as a connecting portion with the blade 23. The outer casing portion 22, which is continuous with the tip side of the main body portion 21, is a straight pipe portion and is joined to the tip surface and inner circumferential surface of the sleeve 5 by welding. The outer casing portion 22 may be formed by first continuously creating pleats and then secondarily processing only the required portion into a straight pipe shape, or by leaving portions that are not pleated during pleating (corrugation) forming.

[0049] An annular groove 52 is provided in the middle of the axial direction n of the connection portion 51 of the sleeve 5, extending over the entire circumferential area of ​​the connection portion 51. This groove 52 is formed in a roughly U-shape in cross-section, and its depth is set to approximately two-thirds of the wall thickness of the connection portion 51. The crimping ring 9 is then crimped from the outside so that it is fitted into the groove 52 with the blade 23 attached to the connection portion 51 of the sleeve 5.

[0050] The system also includes an eight-way crimping machine 4 for crimping the crimping ring 9, and a positioning device 6 for positioning the sleeve 5 together with the flexible tube 2 and the crimping ring 9 relative to the eight-way crimping machine 4. The positioning device 6 moves back and forth in the direction of the sleeve 5's axis n, causing the sleeve 5, the flexible tube 2, and the crimping ring 9 to move back and forth.

[0051] The eight-way crimping machine 4 has eight claws 41, 41 (only two are shown in Figures 5 to 8) that crimp the crimping ring 9 with uniform pressure from eight equally spaced points in the circumferential direction. In addition, each claw 41 of the eight-way crimping machine 4 is located directly outward in the radial direction of the crimping ring 9. The eight-way crimping machine 4 has a positioning piece 42 that protrudes radially inward at a position near the other end of each claw 41 (to the right in Figures 5 to 8), and the crimping ring 9 is positioned on the base end side in the axial direction n of the sleeve 5 (to the left in Figures 5 to 8) by contact with this positioning piece 42. In this case, the crimping ring 9 is in sliding contact with the outer circumferential surface of the blade 23.

[0052] Furthermore, the positioning device 6 has an inner cylindrical member 61 and an outer cylindrical member 62 positioned on the axis n of the sleeve 5. The cylindrical member 61 and the outer cylindrical member 62 are integrally connected to each other at their base ends. The outer casing 22 of the flexible tube 2 is inserted between the cylindrical member 61 and the outer cylindrical member 62, while the tip of the blade 23 is inserted on the outer surface side of the outer cylindrical member 62. In addition, the sleeve 5 is formed such that one end face (the left end face in Figures 5 to 8) abuts against the tip of the outer cylindrical member 62, and in this state, the cylindrical member 61 is longer than the outer cylindrical member 62 so that it is positioned on the outer circumferential surface of the cylindrical member 61 via the outer casing 22.

[0053] The crimping ring 9 is crimped from the radially outward direction so that it is fitted into the groove 52 with the blade 23 attached to the connecting portion 51. The blade 23 is attached to the connecting portion 51 so that when the crimping ring 9 is crimped, its tip is positioned on the base end side (left side in Figures 5 to 8) of the cylindrical member 61 and the outer cylinder member 62, beyond one end face 53 (left end face in Figures 5 to 8) of the groove 52.

[0054] The inner diameter angle of one end face 53 of the groove 52, which is on the base end side of the sleeve 5 (left side in Figures 5 to 8), and the outer diameter angle of one end face 91 of the crimping ring 9 are set such that when the crimping ring 9 is crimped to the groove 52, only the tip of the blade 23, which is positioned on the base end side of the outer cylinder member 62 (left end side in Figures 5 to 8), which is on the base end side of the sleeve 5 than the one end face 53 of the groove 52, is clamped and cut between the one end face 53 of the groove 52 and the one end face 91 of the crimping ring 9. In other words, the inner diameter angle of one end face 53 of the groove 52 and the outer diameter angle of one end face 91 of the crimping ring 9 are the angles at which the sleeve 5 is cut straight across with respect to the axis n of the sleeve 5, and are set to 90°, which is perpendicular to the axis n.

[0055] On the other hand, a gap T greater than the thickness of the blade 23 is provided between the other end face 92 of the crimping ring 9, which is the tip side of the sleeve 5 (the right end side in Figures 5 to 8), and the other end face 54 of the groove 52. A chamfered portion may be provided on at least one of the outer end of the other end face 54 of the groove 52 and the inner end of the other end face 92 of the crimping ring 9.

[0056] Then, the blade 23 is clamped and cut when the crimping ring 9 is crimped with the one end face 53 of the groove 52 and the one end face 91 of the crimping ring 9 aligned in the direction of the sleeve 5's axis n. In addition, the clamped surface 25 of the blade 23 that was clamped and cut between the one end face 53 of the groove 52 and the one end face 91 of the crimping ring 9 is pushed down to the bottom surface 56 along the one end face 53 of the groove 52 as the crimping ring 9 is further crimped. In this case, both the inner circumferential surface of the crimping ring 9 and the bottom surface 56 of the groove 52 are formed as smooth surfaces without irregularities.

[0057] Figure 9 is a cross-sectional view showing the state in which a cap nut attached to the base end of the sleeve 5, in which the blade 23 is crimped into the groove 52 by the crimping ring 9 of Figure 8, is secured to the fixing pipe, and Figure 10 is an enlarged cross-sectional view showing the area around the cap nut in Figure 9.

[0058] As shown in Figures 9 and 10, the base end face of the sleeve 5, which has the blade 23 crimped by the crimping ring 9, is in contact with the base end face (right end face in Figures 9 and 10) of the cap nut 71. The inner surface of the cap nut 71 has a female threaded portion 72 on the tip side, and a tapered portion 73 that expands in diameter from the opening of the base end face toward the female threaded portion 72. The tip side of the outer casing 22 of the flexible tube 2 is inserted through the opening of the base end face of the cap nut 71 and is pressed against it in a tapered, expanded diameter state so as to be in close contact along the tapered portion 73.

[0059] The cap nut 71 is fastened to the fixing pipe 74 via an adapter 75. The tip of the inner circumferential surface of the fixing pipe 74 (the right end in Figures 9 and 10) is formed as a tapered surface that widens in diameter as it approaches the tip surface, and a female thread portion 76 is provided on this tapered surface.

[0060] One end of the outer circumferential surface of the adapter 75 (the left end in Figures 9 and 10) is formed as a tapered surface that decreases in diameter as it approaches the end face, so as to match the tapered surface at one end of the inner circumferential surface of the fixing pipe 74. This tapered surface at one end of the outer circumferential surface of the adapter 75 is provided with a male threaded portion 78 that screws into the female threaded portion 76 at the tip of the inner circumferential surface of the fixing pipe 74. The other end of the outer circumferential surface of the adapter 75 (the right end in Figures 9 and 10) is provided with a male threaded portion 77 that screws into the female threaded portion 72 of the cap nut 71.

[0061] Furthermore, the outer surface of the adapter 75 is rounded on the outer side of the tip of the male threaded portion 77 at the other end, and the male threaded portion 77 at the other end of the adapter 75 is screwed into the female threaded portion 72 of the cap nut 71, thereby pressing the tip of the outer casing 22 of the flexible tube 2 against the tapered portion 73 of the cap nut 71, and thus the outer casing 22 of the flexible tube 2 is firmly connected to the fixed pipe 74 via the adapter 75.

[0062] Next, we will describe other examples of connection methods using the connection structure of the flexible tube 2.

[0063] First, as shown in Figure 5, the outer casing 22 of the flexible tube 2 is inserted between the cylindrical member 61 and the outer cylinder 62 of the positioning device 6, and the tip of the blade 23 is positioned along the outer circumferential surface of the outer cylinder member 62 of the positioning device 6, above the connection portion 51 of the sleeve 5. At this time, the tip of the blade 23 is located beyond the base end of the sleeve 5 and on the base end of the outer cylinder member 62 of the positioning device 6, beyond the one end face 51 of the groove 52. The crimping ring 9 is located on the outer circumferential surface of the blade 23, closer to the main body portion 22 of the flexible tube 2 than the groove 52, and is slightly spaced apart from the positioning pieces 42 of each claw 41 of the eight-way crimping machine 4 toward the blade 23.

[0064] Next, as shown in Figure 6, the positioning device 6 is moved forward toward the main body portion 22 of the flexible tube 2. At this time, the tip of the outer cylindrical member 62 of the sleeve 5 is in contact with one end face (the left end face in the figure) of its connection portion 51, so the sleeve 5 moves forward together with the flexible tube 2 as the positioning device 6 moves forward. The crimping ring 9 also comes into contact with the positioning pieces 42 of each claw 41 of the eight-way crimping machine 4, and in this state slides on the outer circumferential surface of the blade 23 in the opposite direction to the forward movement of the positioning device 6.

[0065] Then, the extension movement of the positioning device 6 is stopped when the positioning is complete, with one end face 91 of the crimping ring 9 sliding on the outer circumferential surface of the blade 23 while in contact with the positioning pieces 42 of each claw 41 of the eight-way crimping machine 4, aligning with one end face 53 of the groove 52 in the direction of the axis n of the sleeve 5.

[0066] Then, as shown in Figure 7, the crimping ring 9 is crimped from eight circumferential points by the claws 41 of the eight-way crimping machine 4, and the crimping ring 9 is fitted into the groove 52 of the sleeve 5 via the blade 23. At this time, the blade 23 is clamped and cut by one end face 53 of the groove 52 and one end face 91 of the crimping ring 9.

[0067] Subsequently, as the crimping ring 9 is further crimped by each of the claws 41 of the eight-way crimping machine 4, the crimped surface 25 of the cut blade 23 is pushed down to the bottom surface 56 while aligned with one end surface 53 of the groove 52.

[0068] Subsequently, as shown in Figure 8, each claw 41 of the eight-way crimping machine 4 is detached radially outward from the crimping ring 9 to complete the crimping of the crimping ring 9, and the positioning device 6 is moved out of the way.

[0069] Therefore, in this embodiment as well, when the blade 23 attached to the connection portion 51 of the sleeve 5 is crimped to the groove 52 by the crimping ring 9, only the tip of the blade 23 that is located beyond the base end of the sleeve 5 beyond the one end face 53 of the groove 52 and towards the base end of the outer cylindrical member 62 of the positioning device 6 is clamped and cut between the one end face 53 of the groove 52 and the one end face 91 of the crimping ring 9, and the clamped surface 25 (cut surface) of the blade 23 is pushed down to the bottom surface 56 along the one end face 53 of the groove 52 as the crimping ring 9 continues to crimp.

[0070] Therefore, when the blade 23 is crimped by the crimping ring 9, the cutting surface 25 of the blade 23 is not pushed down to the bottom surface 56 of the groove 52 and exposed to the outside as the crimping ring 9 continues to crimp. This ensures that the cutting surface 25 of the blade 23 is hidden in the bottom surface 56 of the groove 52, without compromising aesthetics, and reliably prevents damage to parts around the crimping ring 9. Furthermore, it eliminates the need to cut the tip of the blade 23, thereby improving work efficiency.

[0071] Furthermore, since a gap T greater than the thickness of the blade 23 is provided between the other end face 92 of the crimping ring 9 and the other end face 54 of the groove 52, when crimped by the crimping ring 9, the base end of the blade 23 is smoothly guided out from inside the groove 52 through the gap T between the other end face 54 of the groove 52 and the other end face 92 of the crimping ring 9, thereby reliably preventing accidental cutting of the blade 23 between the other end face 54 of the groove 52 and the other end face 92 of the crimping ring 9 when crimped by the crimping ring 9.

[0072] Furthermore, since the clamping surface 25 at the tip of the blade 23 is pushed down to the bottom surface 56 of the groove 52 when the crimping is completed by the crimping ring 9 and is not exposed to the outside, there is no need to provide a ring cover or the like on the cap nut 71 to cover the exposed tip of the blade 23 from the outside.

[0073] Furthermore, since the crimping ring 9 is exposed when the female thread portion 72 of the cap nut 71 is screwed onto the male thread portion 77 of the adapter 75, if this crimping ring 9 is held with pliers or the like (not shown), the rotational force when screwing the female thread portion 72 of the cap nut 71 onto the male thread portion 77 of the adapter 75 will not be transmitted to the outer casing 22 and blade 23 of the flexible tube 2. This makes it possible to avoid twisting of the outer casing 22 and blade 23 of the flexible tube 2 due to the rotational force when screwing the cap nut 71 onto the adapter 75.

[0074] It should be noted that the present invention is not limited to the embodiments described above, but encompasses a variety of other modifications. For example, in the first embodiment, both the inner circumferential surface of the crimping ring 3 and the bottom surface 16 of the groove 12 are formed as smooth surfaces. However, as shown in Figures 11 and 12, sawtooth-shaped irregularities 81, 81 may be provided on the bottom surface 16 of the groove 12 and the inner circumferential surface of the crimping ring 3 to actively apply frictional force to the blade 23 that is pushed up to the bottom surface 16 of the groove 12 as the crimping ring 3 progresses.

[0075] In this case, the uneven surfaces 81, 81 provided on the bottom surface 16 of the groove 12 and the inner circumferential surface of the crimping ring 3 effectively increase the frictional force on the blade 23 when it is crimped by the crimping ring 3, which is very advantageous in reliably preventing the blade 23 from falling out of the groove 12 when a load is applied.

[0076] Furthermore, it is not necessary to provide the uneven surfaces 81, 81 on the bottom surface 16 of the groove 12 and the inner circumferential surface of the crimping ring 3, respectively; the uneven surfaces may be provided on only one of the bottom surface of the groove or the inner circumferential surface of the crimping ring. Moreover, the shape of the uneven surfaces is not limited to a sawtooth shape; any uneven surface with a small contact area that can effectively increase the frictional force against the blade is acceptable.

[0077] Furthermore, in each of the above embodiments, the inner diameter angles of the one end faces 13, 53 of the grooves 12, 52 and the outer diameter angles of the one end faces 31, 91 of the crimping rings 3, 9 were set to 90°, which is perpendicular to the axes m, n of the pipe member 1 and the sleeve 5, respectively. However, the inner diameter angles of the one end faces of the grooves and the outer diameter angles of the one end faces of the crimping rings are not limited to 90°. Any angle at which the blade is clamped and cut between the one end face of the groove and the one end face of the crimping ring is acceptable, and the angle with respect to the axis of the connecting members such as the pipe member and the sleeve does not have to be 90°.

[0078] Furthermore, in the first embodiment, chamfered portions 15 and 33 were provided on the outer end of the other end face 14 of the groove 12 and on the inner end of the other end face 32 of the crimping ring 3, respectively. However, chamfered portions may be provided on only one of the outer end of the other end face of the groove and the inner end of the other end face of the crimping ring. [Explanation of Symbols]

[0079] 1. Pipe component (component to be connected) 11 Connection part 12 grooves 13 One end face of the groove 14 Other end face of the groove 15 Chamfered section 16. Base 2. Metal flexible tube 21 Main body 23 Blades 24. Cutting surface 25. Cutting surface 3 crimping ring 31 One end face of a crimping ring 32 Other end face of crimping ring 33 Chamfered section 5. Sleeve (connection target component) 52 grooves 53 One end face of the groove 54 Other end face of the groove 56 Bottom 81 Uneven part 9 crimping ring 91 One end face of a crimping ring 92 Other end face of crimping ring S Gap T gap m-axis n-axis

Claims

1. A connection method for connecting a blade, which is attached to the outer surface of the main body of a metal flexible tube, to a connection portion provided on the tip side of a cylindrical member to be connected, The connection portion of the member to be connected comprises an annular groove recessed in the circumferential direction midway along the axial direction of the connection portion, and a crimping ring that crimps the blade into the groove while it is externally attached to the connection portion of the member to be connected, The inner diameter angle of one end face of the groove that forms the base end of the member to be connected and the outer diameter angle of one end face of the crimping ring are set at angles such that when the crimping ring is crimped into the groove, only the tip side of the blade is clamped and cut between one end face of the groove and one end face of the crimping ring. When crimping the crimping ring into the groove, the blade is attached to the connection portion such that its tip is positioned on the base end side of the member to be connected, rather than on one end face of the groove. After the tip end of the blade, which has been attached to the connection part, is clamped and cut by one end face of the crimping ring and one end face of the groove, A method for connecting a metal flexible tube, characterized in that the cutting surface of the blade, which has been cut by clamping, is pushed down to the bottom surface while being aligned with one end face of the groove as the crimping ring is crimped.

2. A connection structure for connecting a blade, which is attached to the outer surface of the main body of a metal flexible tube, to a connection portion provided on the tip side of a cylindrical member to be connected, The connection portion of the member to be connected comprises an annular groove recessed in the circumferential direction midway along the axial direction of the connection portion, and a crimping ring that crimps the blade into the groove while it is externally mounted on the connection portion of the member to be connected, The inner diameter angle of one end face of the groove, which is on the base end side of the member to be connected, and the outer diameter angle of one end face of the crimping ring are set at angles such that when the crimping ring is crimped into the groove, only the tip side of the blade, which is attached to the connection part, is clamped between the one end face of the groove and the one end face of the crimping ring, such that the tip is positioned on the base end side of the member to be connected, rather than on the one end face of the groove. A connection structure for a metal flexible tube, characterized in that the cutting surface of the blade, which is cut between one end face of the groove and one end face of the crimping ring, is pushed down to the bottom surface along one end face of the groove as the crimping ring is crimped.

3. The metal flexible tube connection structure according to claim 2, wherein a gap greater than the thickness of the blade is provided between the other end face of the crimping ring, which is the tip end of the member to be connected, and the other end face of the groove.

4. The metal flexible tube connection structure according to claim 3, wherein a chamfered portion is provided on at least one of the outer end of the other end face of the groove and the inner end of the other end face of the crimping ring.

5. The metal flexible tube connection structure according to claim 3, wherein the inner diameter angle of one end face of the groove and the outer diameter angle of one end face of the crimping ring are set to 90° perpendicular to the axis of the member to be connected.

6. The metal flexible tube connection structure according to any one of claims 3 to 5, wherein at least one of the bottom surface of the groove and the inner circumferential surface of the crimping ring is provided with an uneven surface that actively applies frictional force to the blade which is pushed down to the bottom surface of the groove when the crimping ring is crimped.

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