Protection tube of electric cable

Abstract

To provide a protection tube which can secure a sufficient space between an outer surface of an inner tube and an inner surface of an outer tube and maintain a position of the inner tube properly.SOLUTION: A protection tube 1 has: a flexible outer tube 20; a flexible inner tube 30 disposed at the inner side of the outer tube 20; and a support member 50 located between an inner surface of the outer tube 20 and an outer surface of the inner tube 30. The support member 50 has an inner contact part 52 and an outer contact part 51. The inner contact part 52 contacts with the outer surface of the inner tube 30 and the outer contact part 51 contacts with the inner surface of the outer tube 20. A distance L1 between the outer contact part 51 and a center line C of the inner tube 30 is larger than a distance L2 between the inner contact part 52 and the center line C of the inner tube 30.SELECTED DRAWING: Figure 4A

Description

[Technical field]

[0001] The present invention relates to a protective tube through which an electric cable is passed to protect the same. [Background technology]

[0002] Protective pipes are sometimes used to protect cables such as electric cables and superconducting cables from external heat. Patent Document 1 discloses a thermally insulated pipe consisting of an inner pipe and an outer pipe as such a protective pipe. A spacer and a fireproof material are disposed between the inner pipe and the outer pipe. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2001-4076 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a protective tube having an inner tube and an outer tube, it is desirable to secure a sufficient space between the outer surface of the inner tube and the inner surface of the outer tube. Also, if the position of the inner tube is shifted from the center of the outer tube, the distance between the inner tube and the outer tube becomes locally close, which reduces the protective performance. Therefore, it is desirable to maintain the position of the inner tube at the center of the outer tube.

[0005] An object of the present disclosure is to provide a protective tube that ensures a sufficient space between the outer surface of the inner tube and the inner surface of the outer tube and can properly maintain the position of the inner tube. [Means for solving the problem]

[0006] (1) The protective tube proposed in this disclosure includes a flexible outer tube, a flexible inner tube disposed inside the outer tube and through which an electric cable passes, and a support member located between the inner surface of the outer tube and the outer surface of the inner tube, formed of a wire, and surrounding the outer periphery of the inner tube. The support member has a first portion and a second portion separated from each other in a direction along the wire, the first portion contacting the outer surface of the inner tube, the second portion contacting the inner surface of the outer tube, and the distance between the second portion and the center line of the inner tube is greater than the distance between the first portion and the center line of the inner tube. This ensures a sufficient space between the outer surface of the inner tube and the inner surface of the outer tube, and the position of the inner tube can be appropriately maintained.

[0007] (2) In the protective tube of (1), the support member may be a spring wound around the outer periphery of the inner tube. This makes it relatively easy to realize deformation of the support member in accordance with bending of the inner tube and the outer tube.

[0008] (3) In the protective tube of (1), the first portion and the second portion may be spaced apart in a direction along the center line. This increases the distance between the first portion and the second portion, so that when the outer tube is heated, heat transfer to the inner tube via the second portion and the first portion can be suppressed.

[0009] (4) In the protective tube of (1), the support member may have a shape wound around the outer periphery of the inner tube, and may have a large diameter portion and a small diameter portion separated in a direction along the center line, the large diameter portion having the second portion, and the small diameter portion having the first portion. This makes it easy to ensure a sufficient space between the outer surface of the inner tube and the inner surface of the outer tube.

[0010] (5) In the protective tube of (1), the support member may be polygonal when viewed in a direction along a center line of the inner tube. The second portion may be a vertex of the polygon, and the first portion may be a portion between two adjacent vertices of the polygon.

[0011] (6) In the protective tube of (1), the angle between the angular position of the first portion and the angular position of the second portion in a circumferential direction around a center line of the protective tube may be 60 degrees or less.

[0012] (7) In the protective tube of (1), the inner tube and the outer tube may have a tube body made of an electrically conductive material, and the tube body of the inner tube and the tube body of the outer tube may be electrically connected to each other. This makes it possible to prevent electric charges from accumulating in the inner tube.

[0013] (8) The protective tube of (1) may further include a conductive plate surrounding the outer periphery of the inner tube. The conductive plate may be located at an end of the inner tube and an end of the outer tube, and may be electrically connected to the inner tube and the outer tube. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a diagram showing the appearance of a protective tube proposed in the present disclosure. [Diagram 2] FIG. 2 is a cross-sectional view of the protective tube shown in FIG. [Diagram 3] 2 is a cross-sectional view showing a joint portion provided at an end portion of the protective tube shown in FIG. 1. [Figure 4A] 11A and 11B are diagrams showing examples of support members that the protective tube has. [Figure 4B] 4B is a view of the support member shown in FIG. 4A as viewed in a direction along the center line of the protective tube. [Figure 5A] 13A and 13B are diagrams illustrating another example of a support member. [Figure 5B] 5B is a view of the support member shown in FIG. 5A as viewed in a direction along the center line of the protective tube. [Figure 6A] 13A and 13B are diagrams illustrating yet another example of a support member. [Figure 6B] 6B is a view of the support member shown in FIG. 6A as viewed in a direction along the center line of the protective tube. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of a protective tube proposed in the present disclosure will be described. In this specification, a protective tube 1 shown in FIG. 1 and the like will be described as an example of the embodiment.

[0016] [Outer and inner pipes] As shown in FIG. 2, the protective tube 1 has an outer tube 20 and an inner tube 30 disposed inside the outer tube 20. The inner tube 30 is supported by a support member 50 inside the outer tube 20, and the inner tube 30 and the outer tube 20 have a common center line C. A space is secured between the inner surface of the outer tube 20 and the outer surface of the inner tube 30 by the action of the support member 50. When the protective tube 1 is used, for example, an electric cable (not shown) is disposed inside the inner tube 30. The protective tube 1 can protect the electric cable. For example, the electric cable can be protected from external temperature changes. In one example, a fireproof material (thermal insulation material) is filled in this space. A layer of air may be formed without inserting a fireproof material in this space.

[0017] Both the outer pipe 20 and the inner pipe 30 are flexible pipes. Therefore, the outer pipe 20 and the inner pipe 30 can be bent to fit the shape of the location where the electric cable is laid. The outer pipe 20 and the inner pipe 30 have pipe bodies 21 and 31, respectively, which are composed of a metal band wound in a spiral shape around the center line C of the protective pipe 1. A part of the metal band of the outer pipe 20 (for example, the part indicated by the symbol M1 in FIG. 2) is meshed and connected to another part of the metal band located adjacently in the direction along the center line C of the protective pipe 1 (for example, the part indicated by the symbol M2 in FIG. 2). (Hereinafter, the "direction along the center line C" of the protective pipe 1 will be referred to as the center line direction.) The two adjacent parts (M1 and M2) are connected to each other so that the relative positions of the two parts are allowed to change. This allows the outer pipe 20 to be bent. Similarly, a portion of the metal band of the inner tube 30 (for example, the portion indicated by symbol N1 in FIG. 2) engages and is connected to another portion of the metal band adjacent to it in the center line direction of the protective tube 1 (for example, the portion indicated by symbol N2 in FIG. 2). The two adjacent portions (N1 and N2) are connected to each other so that the relative positions of the two adjacent portions are allowed to change, thereby allowing the inner tube 30 to be bent. The tube bodies 21 and 31 are formed of an electrically conductive material. The material of the tube bodies 21 and 31 may be, for example, iron or stainless steel.

[0018] 2, the metal band of the outer tube 20 has a first engagement portion 21a along one edge thereof and a second engagement portion 21b along the opposite edge thereof. The first engagement portion 21a is, for example, substantially U-shaped and opens toward the inside of the protective tube 1, and the second engagement portion 21b is, for example, substantially U-shaped and opens toward the outside of the protective tube 1. The first engagement portion 21a of one of two adjacent portions M1 and M2 is engaged with and connected to the second engagement portion 21b of the other portion.

[0019] 2, the outer pipe 20 may have a coating layer 22 made of resin on its outside. The coating layer 22 is formed on the entire outer circumferential surface of the spirally wound metal band. The coating layer 22 can prevent rainwater and the like from entering the inside of the outer pipe 20. The coating layer 22 can be made of, for example, polyvinyl chloride.

[0020] 2, the metal band of the inner pipe 30 has a first engagement portion 31a along one edge thereof and a second engagement portion 31b along the opposite edge thereof. Each of the first engagement portion 31a and the second engagement portion 31b is, for example, hook-shaped. The first engagement portion 31a of one of two adjacent portions N1 and N2 is engaged with and connected to the second engagement portion 21b of the other portion.

[0021] A gap S is formed between the first engagement portion 21a and the second engagement portion 21b that are meshed with each other in the outer pipe 20. Therefore, the change in the relative position of two adjacent portions M1 and M2 in the outer pipe 20 is allowed to be larger than the change in the relative position of two adjacent portions N1 and N2 in the inner pipe 30. This allows the outer pipe 20, which has a larger diameter than the inner pipe 30, to be bent sufficiently.

[0022] [Coating layer of inner tube] 2, the inner pipe 30 may have a coating layer 32 made of resin on its outside. The coating layer 32 is formed on the entire outer circumferential surface of the spirally wound metal strip. The coating layer 32 can, for example, prevent moisture from penetrating into the inside of the inner pipe 30.

[0023] [Lid assembly] 2, the protective tube 1 has a lid assembly 40 at both ends. The lid assembly 40 is attached to the end of the outer tube 20 and the end of the inner tube 30, and closes the space between the inner surface of the outer tube 20 and the outer surface of the inner tube 30. An opening 41g is formed in the center of the lid assembly 40, penetrating the protective tube 1 in the direction of its centerline, and the electric cable is passed through the inside of this opening 41g.

[0024] 3, the lid assembly 40 has a lid main body 41. The lid main body 41 has an outer cylinder portion 41a fixed to the outer tube 20. An end of the outer tube 20 is fitted inside the outer cylinder portion 41a. The outer cylinder portion 41a is fixed to the end of the outer tube 20 by, for example, a nut 42 fitted to the outside of the outer tube 20. The outer cylinder portion 41a is fitted inside the nut 42, and a screw formed on the outer peripheral surface of the outer cylinder portion 41a engages with the nut 42.

[0025] In the example of the protective tube 1, as shown in FIG. 3, a seal member 43 is disposed inside the nut 42. The seal member 43 is made of a flexible material (e.g., rubber or elastomer). For example, a packing can be used as the seal member 43. When the nut 42 is tightened, the outer cylinder portion 41a approaches the nut 42. At this time, the lid assembly 40 is pressed against the end face of the outer tube 20 (the end face 23c of the end fitting 23 described later) in the center line direction of the protective tube 1. Furthermore, when the nut 42 is tightened, the seal member 43 is compressed by the outer cylinder portion 41a and the nut 42 and pressed against the outer peripheral surface of the outer tube 20. As a result, the positions of the nut 42 and the lid main body 41 in the center line direction of the protective tube 1 are firmly fixed.

[0026] When the seal member 43 is compressed by the outer tube portion 41a and the nut 42, the end of the seal member 43 enters between the end 41f of the outer tube portion 41a and the outer peripheral surface of the outer tube 20. As a result, the gap between the lid assembly 40 and the outer tube 20 is sealed by the seal member 43. The seal member 43 can prevent external moisture from penetrating into the inside of the outer tube 20 through the gap between the lid body 41 and the outer surface of the outer tube 20. In addition, when the seal member 43 is compressed by the outer tube portion 41a and the nut 42, the end of the seal member 43 may press the end of the outer peripheral portion 23d of the end fitting 23 described later against the end 41f of the outer tube portion 41a of the lid body 41.

[0027] The fixing structure of the outer tube 20 and the lid body 41 is not limited to the example of the protective tube 1. For example, a ring having a screw formed on its outer circumferential surface may be fitted onto the outside of the outer tube 20, and the lid body 41 may be engaged with the ring.

[0028] In the example of the protective tube 1, as shown in FIG. 3, an annular conductive plate 44 is disposed inside the lid body 41. The conductive plate 44 is fitted to the outside of the inner tube 30. The outer tube 20 has an end fitting 23 that covers the end face of the tube body 21. The conductive plate 44 and the end face 23c of the end fitting 23 face each other in the center line direction of the protective tube 1. When the nut 42 is tightened, the lid body 41 presses the conductive plate 44 against the end fitting 23, and they are in close contact. The conductive plate 44 is formed of a material having a higher electrical conductivity than the lid body 41, for example. Stainless steel, copper, etc. may be used as the material of the conductive plate 44. As will be described in detail later, the tube body 21 of the outer tube 20 and the tube body 31 of the inner tube 30 are electrically connected via this conductive plate 44. Note that the lid assembly 40 does not necessarily have to have the conductive plate 44. In this case, the lid body 41 may be directly attached to the end surface 23c of the end fitting 23.

[0029] 3, the lid body 41 has an inner cylindrical portion 41b. An end portion of the inner tube 30 is fitted inside the inner cylindrical portion 41b. This allows the center of the outer tube 20 and the center of the inner tube 30 to coincide with each other at the end portion of the protective tube 1.

[0030] Furthermore, the lid assembly 40 is in close contact with the end of the inner tube 30 in the center line direction of the protective tube 1. In the example of the protective tube 1, the inner tube 30 has an end fitting 33 that covers the end face of the tube body 31. The inner cylinder portion 41b has, at its end, a contact portion 41d that protrudes toward the center of the protective tube 1 and faces an end face 33d of the end fitting 33 in the center line direction of the protective tube 1. The end face 33d is located in the center line direction of the protective tube 1 with respect to the end face of the tube body 31, and is a portion that covers the end face of the inner tube 30.

[0031] The tube body 31 of the inner tube 30 and the tube body 21 of the outer tube 20 are electrically connected. In the example of the protective tube 1, the end fitting 23 of the outer tube 20 has a tubular portion 23a that runs along the inner surface of the tube body 21 and a flange portion 23b that is formed at the end of the tubular portion 23a and hooked onto the tube body 21, and is electrically connected to the tube body 21 at the tubular portion 23a and the flange portion 23b. In addition, the end face 23c of the end fitting 23 and the conductive plate 44 are in close contact with each other and are electrically connected. Furthermore, the end fitting 33 of the inner tube 30 has a tubular portion 33a that runs along the inner surface of the inner tube 30 and a flange portion 33b that is formed at the end of the tubular portion 33a and hooked onto the tube body 31, and is electrically connected to the tube body 31 at the tubular portion 33a and the flange portion 33b. The end fitting 33 has an outer circumferential portion 33c that covers the outer circumferential surface of the end of the inner tube 30. The end 33e of the outer circumferential portion 33c is in contact with and electrically connected to the conductive plate 44. In this manner, the pipe body 31 of the inner pipe 30 and the pipe body 21 of the outer pipe 20 are electrically connected to each other via the conductive plate 44.

[0032] Furthermore, the end 33e of the outer circumferential portion 33c of the end fitting 33 may be in contact with the inner cylindrical portion 41b of the lid body 41. In this case, the tube body 31 of the inner tube 30 is electrically connected to the tube body 21 of the outer tube 20 via the lid body 41.

[0033] The lid assembly 40 may have a joint portion 41e that connects two protective tubes 1. In the example of the protective tube 1, the joint portion 41e is formed in the lid body 41. A screw is formed on the outer peripheral surface of the joint portion 41e. The joint portion 41e is connected to the adjacent protective tube 1, for example, by using a nut 49 shown in FIG. 2, or is connected to the adjacent protective tube 1 via a connector that engages with the screw of the joint portion 41e. The structure of the joint portion 41e is not limited to the example of the protective tube 1, and for example, a screw may be formed on the inner peripheral surface of the joint portion 41e.

[0034] [Support material] 2, the protective tube 1 has a support member 50 made of a wire and disposed between the inner surface of the outer tube 20 and the outer surface of the inner tube 30. The support member 50 surrounds the outer periphery of the inner tube 30 and supports the inner tube 30 inside the outer tube 20. More specifically, the support member 50 supports the inner tube 30 so that the center line of the outer tube 20 (center line C of the protective tube 1) and the center line of the inner tube 30 coincide with each other. The wire functioning as the support member 50 is a metal wire that can deform in accordance with the bending of the inner tube 30 and the outer tube 20, and is, for example, a piano wire, a hard steel wire, a stainless steel wire, an oil-tempered wire, a phosphor bronze wire, or the like.

[0035] The support member 50 is a member wound around the center line C of the protective tube 1. In other words, the support member 50 is a spring. By using a spring in this manner, it is relatively easy to realize the deformation of the support member 50 in accordance with the bending of the inner tube 30 and the outer tube 20.

[0036] 4A, the support member 50 has an outer contact portion 51 (large diameter portion) in contact with the inner surface of the outer tube 20, and an inner contact portion 52 (small diameter portion) in contact with the outer surface of the inner tube 30. The outer contact portion 51 and the inner contact portion 52 can appropriately maintain the position of the inner tube 30 in the outer tube 20. In the example of the protective tube 1, each of the outer contact portion 51 and the inner contact portion 52 is a portion wound multiple times around the center line C. The inner tube 30 is disposed inside the inner contact portion 52.

[0037] 4A, the outer contact portion 51 has a larger diameter than the inner contact portion 52. Therefore, the distance L1 between the outer contact portion 51 and the center line of the inner tube 30 (the center line C of the protective tube 1) is larger than the distance L2 between the inner contact portion 52 and the center line of the inner tube 30 (the center line C of the protective tube 1). This structure of the support member 50 ensures a sufficient space between the outer tube 20 and the inner tube 30.

[0038] In the example shown in the figure, the outer contact portion 51 (large diameter portion) is in contact with the inner surface of the outer tube 20 over the entire area in the center line direction of the protective tube 1. Similarly, the inner contact portion 52 (small diameter portion) is in contact with the outer surface of the inner tube 30 over the entire area in the center line direction of the protective tube 1. This makes it easier to stabilize the position of the inner tube 30 inside the outer tube 20. Unlike the example shown in the figure, the outer contact portion 51 may have a particularly large diameter at the center of the protective tube 1 in the center line direction, and may be in contact with the inner surface of the outer tube 20 only at this center portion. Also, the inner contact portion 52 may have a particularly small diameter at the center of the protective tube 1 in the center line direction, and may be in contact with the outer surface of the inner tube 30 only at this center portion.

[0039] As shown in FIG. 4B, the outer contact portion 51 and the inner contact portion 52 are connected to each other via a connecting portion 53 therebetween. The connecting portion 53 is a part of the wire material constituting the support member 50. Therefore, the outer contact portion 51 and the inner contact portion 52 are separated from each other in a direction along the wire material constituting the support member 50, in other words, in a direction in which the wire material is wound. In addition, in the example of the support member 50, the outer contact portion 51 and the inner contact portion 52 are also separated from each other in a center line direction of the protective tube 1. For this reason, the distance between the outer contact portion 51 and the inner contact portion 52 becomes large, and when the outer tube 20 is heated, for example, it is possible to suppress the transfer of heat to the inner tube 30 via the outer contact portion 51 and the inner contact portion 52.

[0040] 4A, the support member 50 has a plurality of outer contact portions 51 spaced apart in the direction of the center line of the protective tube 1. Similarly, the support member 50 has a plurality of inner contact portions 52 spaced apart in the direction of the center line of the protective tube 1. The outer contact portions 51 and the inner contact portions 52 are formed alternately and are distributed throughout the protective tube 1. Therefore, the protective tube 1 can be bent at any position while maintaining the inner tube 30 at the center of the protective tube 1.

[0041] 4A and 4B. For example, the support member 50 does not necessarily have to be a spring wound around the center line C. Even in this case, the support member 50 may have an outer contact portion 51 that is relatively far from the center line of the inner tube 30 and an inner contact portion 52 that is relatively short from the center line of the inner tube 30, and they may be spaced apart in the direction along the wire.

[0042] [Modification of the support member] 4A and 4B, the support member 50 is circular when viewed in the center line direction of the protective tube 1. The shape of the support member 50 is not limited to this. The support member 50 may be, for example, polygonal when viewed in the center line direction of the protective tube 1.

[0043] 5A and 5B are diagrams showing a support member 150 as a modified example of the support member. The support member 150 is a wire material wound around the center line C of the protective tube 1 and surrounding the outer periphery of the inner tube 30, similar to the support member 50 described above. In other words, the support member 150 is also a spring. The support member 150 is different from the support member 50 described above in that the support member 150 is triangular when viewed in the center line direction of the protective tube 1, as shown in FIG. 5B. More specifically, the support member 150 is an equilateral triangle. The support member 150 has a straight line portion 150a that forms one side of the triangle. The inner tube 30 is surrounded by three consecutive straight line portions 150a. Hereinafter, the wire material that forms one triangle (three consecutive straight line portions 150a) is referred to as a unit support portion. As shown in FIG. 5A, a plurality of unit support members (triangular portions) are lined up in the center line direction of the protective tube 1. This allows the protective tube 1 to be bent at any position while maintaining the inner tube 30 at the center of the protective tube 1.

[0044] As shown in FIG. 5B, the support member 50 has a plurality of outer contact portions 151 in contact with the inner surface of the outer tube 20 and a plurality of inner contact portions 152 in contact with the outer surface of the inner tube 30. In the example of the protective tube 1, the outer contact portion 151 is the apex of a triangle (the end of each straight portion 150a). The inner contact portion 152 is the contact point of the straight portion 150a with the outer peripheral surface of the inner tube 30, and is located between the two apexes of the triangle. Therefore, the inner contact portion 152 and the outer contact portion 151 are separated from each other in the direction along the wire material constituting the support member 150 (the extension direction of each straight portion 150a). The angle between the angular position of the outer contact portion 151 and the angular position of the inner contact portion 152 in the circumferential direction centered on the center line C of the protective tube 1 (angle θ in FIG. 5B) may be 60 degrees or less. A distance L3 between the outer contact portion 151 and the center line of the inner tube 30 (center line C of the protective tube 1) is greater than a distance L4 between the inner contact portion 152 and the center line of the inner tube 30 (center line C of the protective tube 1).

[0045] The shape of the support member when viewed in the center line direction of the protective tube 1 does not have to be triangular. The support member may be rectangular or pentagonal. In other words, the shape of the support member when viewed in the center line direction of the protective tube 1 may be polygonal. For example, when the support member is rectangular, the support member makes one revolution around the center line C of the protective tube 1 by four straight parts. In this case, the outer contact part is the end of the straight part, and the inner contact part is the contact point with the inner tube 30 at each straight part. Even if the shape of the support member is a polygon other than a triangle, the angle θ between the angular position of the outer contact part and the angular position of the inner contact part in the circumferential direction centered on the center line C of the protective tube 1 may be 60 degrees or less. For example, when the support member is rectangular, the angle θ between the angular position of the outer contact part and the angular position of the inner contact part may be 45 degrees or less.

[0046] In the support member 150, the angular positions of the multiple outer contact parts 151 are the same in the center line direction of the protective tube 1. For example, the multiple outer contact parts 151 located above the inner tube 30 are aligned linearly in the center line direction. Similarly, the multiple outer contact parts 151 located above the inner tube 30 are aligned linearly in the center line direction. The multiple outer contact parts 151 located at the 8 o'clock position with respect to the inner tube 30 (the outer contact parts 151 located at the lower left in FIG. 5B) are aligned linearly in the center line direction, and the multiple outer contact parts 151 located at the 4 o'clock position with respect to the inner tube 30 (the outer contact parts 151 located at the lower right in FIG. 5B) are also aligned linearly in the center line direction. Similarly, the multiple inner contact parts 152 are also aligned linearly in the center line direction.

[0047] However, the angular positions of the multiple outer contact portions may vary in the circumferential direction around the center line C of the protective tube 1. FIGS. 6A and 6B are diagrams for explaining such a configuration. As shown in FIG. 6B, the support member 250 has multiple outer contact portions 251 (251a to 251f) and multiple inner contact portions 252. In this diagram, the three outer contact portions 251a, 251b, and 251c are located at the vertices of one triangle (unit support member). An inner contact portion 252 is provided between the two outer contact portions 251a and 251b, and an inner contact portion 252 is also provided between the two outer contact portions 251b and 251c. The three outer contact portions 251d, 251e, and 251f are located at the vertices of the adjacent triangle (unit support member). In the adjacent triangle, an inner contact portion 252 is provided between two outer contact portions 251e and 251d, and an inner contact portion 252 is also provided between two outer contact portions 251f and 251e.

[0048] The angular position of each unit support member (triangle) is shifted by an angle θ with respect to another unit support member (triangle) located adjacently in the center line direction of the protective tube 1. In FIG. 6B, only three unit support members are shown as an example. The angle θ is, for example, an angle of 90 degrees or less. The angle θ may be 60 degrees or less. The angle θ may be 30 degrees or less.

[0049] The support member 250 may have a connecting portion 253 that connects two unit support members adjacent to each other in the center line direction of the protective tube 1.

[0050] [Manufacturing method] A manufacturing method of the protective tube 1 will be described. First, the outer tube is cut to a length corresponding to the length of a plurality of protective tubes, to obtain the outer tube 20 of a length required at the site where the protective tube 1 is used. Similarly, the inner tube is cut to a length corresponding to the length of a plurality of protective tubes, to obtain the inner tube 30 of a length required at the site where the protective tube 1 is used. This cutting may be performed at a manufacturing plant for the protective tube 1, or may be performed at the site where the protective tube 1 is used. An end fitting 33 is attached to the end of the inner tube 30, and an end fitting 23 is attached to the end of the outer tube 20. Then, the inner tube 30 is inserted inside the outer tube 20 (insertion process). In addition, a support member 50 is inserted between the inner surface of the outer tube 20 and the outer surface of the inner tube 30. This supports the inner tube 30 on the center line of the outer tube 20. The insertion of the support member 50 may be performed before the insertion process of the inner tube 30, or may be performed simultaneously with the insertion process of the inner tube 30. For example, the inner tube 30 may be inserted inside the support member 50 , and the inner tube 30 and the support member 50 may be inserted together inside the outer tube 20 .

[0051] Finally, another lid assembly 40 is attached to the other end of the outer pipe 20 and the other end of the inner pipe 30. This results in one protective pipe 1. At the site of use, the two protective pipes 1 are connected to each other by utilizing the joint portion 41e formed in the lid assembly 40.

[0052] [summary] As described above, the protective tube 1 includes the flexible outer tube 20, the flexible inner tube 30 disposed inside the outer tube 20, and the support member 50, which is located between the inner surface of the outer tube 20 and the outer surface of the inner tube 30, is made of a wire, and surrounds the outer periphery of the inner tube 30. The support member 50 includes the inner contact portions 51·151·251 and the outer contact portions 51·151·251 that are spaced apart from each other in the direction along the wire. The inner contact portions 52·152·252 are in contact with the outer surface of the inner tube 30, and the outer contact portions 51·151·251 are in contact with the inner surface of the outer tube 20. The distances L1·L3 between the outer contact portions 51·151·251 and the center line C of the inner tube 30 are greater than the distances L2·L4 between the inner contact portions 52·152·252 and the center line C of the inner tube 30. According to this, a sufficient space can be secured between the outer surface of the inner pipe 30 and the inner surface of the outer pipe 20 by the support member 50, and the position of the inner pipe 30 can be appropriately maintained by the support member 50.

[0053] It should be noted that the protective tube proposed in this disclosure is not limited to the protective tube 1 described above.

[0054] For example, the support member disposed between the inner tube 30 and the outer tube 20 does not necessarily have to be a spring. The support member 50 is a wire that can deform in response to bending of the inner tube 30 and the outer tube 20, but does not have to be elastically deformable in the direction of the center line of the protective tube 1. [Explanation of symbols]

[0055] 1 protective tube, 20 outer tube, 21 tube body, 21a first engagement portion, 21b second engagement portion, 22 coating layer, 23 end fitting, 23a tube portion, 23b flange portion, 23c end surface, 30 inner tube, 31 tube body, 31a first engagement portion, 31b second engagement portion, 32 coating layer, 33 end fitting, 33a tube portion, 33b flange portion, 40 lid assembly, 50 support member, 41 lid body, 41a outer tube portion, 41b inner tube portion, 41d: contact portion, 41e: joint portion, 42 nut, 43 seal member, 44 conductive plate, 49 nut, 50 support member, 51 outer contact portion (large diameter portion), 52 inner contact portion (small diameter portion), 53 connection portion, 150 support member, 150a Straight portion, 151 outer contact portion, 152 inner contact portion, 250 support member, 251, 251a to 251f outer contact portions, 252: inner contact portion, C center line of protective tube.

Claims

1. A flexible outer tube and a flexible inner tube disposed inside the outer tube; a support member that is located between an inner surface of the outer tube and an outer surface of the inner tube, the support member being made of a wire and surrounding an outer periphery of the inner tube; The support member has a first portion and a second portion spaced apart from each other in a direction along the wire, the first portion is in contact with an outer surface of the inner tube; the second portion is in contact with an inner surface of the outer tube, The distance between the second portion and the center line of the inner pipe is greater than the distance between the first portion and the center line of the inner pipe. Cable protection tube.

2. The support member is a spring wound around the outer periphery of the inner tube. The protective tube according to claim 1 .

3. The first portion and the second portion are spaced apart in a direction along the centerline. The protective tube according to claim 1 .

4. the support member has a shape wound around an outer periphery of the inner tube, and has a large diameter portion and a small diameter portion spaced apart in a direction along the center line, the large diameter portion has the second portion, The reduced diameter portion has the first portion. The protective tube according to claim 1 .

5. the support member is polygonal when viewed in a direction along a centerline of the inner tube; the second portion being a vertex of the polygon; The first portion is a portion between two adjacent vertices of the polygon. The protective tube according to claim 1 .

6. The angle between the angular position of the first portion and the angular position of the second portion in the circumferential direction around the center line of the protective tube is 60 degrees or less. The protective tube according to claim 1 .

7. The inner tube and the outer tube each have a tube body made of an electrically conductive material, The tube body of the inner tube and the tube body of the outer tube are electrically connected to each other. The protective tube according to claim 1 .

8. The device further includes a conductive plate surrounding an outer periphery of the inner tube, The conductive plate is located at an end of the inner tube and an end of the outer tube, and is electrically connected to the inner tube and the outer tube. The protective tube according to claim 1 .

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