JP2017175802A - Corrugated pipe, corrugated pipe stock thereof, and manufacturing method for corrugated pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a corrugated pipe and the like capable of preventing an inserted electric wire from being exposed out of the pipe without a hinge part provided thereon, being light, and with excellent bendability.SOLUTION: A corrugated pipe 1 comprises a plurality of crest parts 3 and valley parts 5 extending in a circumferential direction, alternately formed in a pipe axis repeatedly with a prescribed intervals. The corrugated pipe 1 further comprises an inner overlapped section 7a and an outer overlapped section 7b at both ends in a circumferential direction in a cross section which is perpendicular to a longitudinal direction of the corrugated pipe. A curving connection section 9 is a connecting part between the inner overlapped section 7a and the outer overlapped section 7b. In the corrugated pipe 1, the curving connection section 9 reduces a diameter thereof so as to be able to overlap respective the crest parts 3 with each other and respective the valley parts 5 with each other of the inner overlapped section 7a and the outer overlapped section 7b. Moreover, a center of curvature radius of at least any one of the inner overlapped section 7a and the outer overlapped section 7b is arranged in an offset position from a center position of the curving connection section 9.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a corrugated tube having an opening continuous in the longitudinal direction and capable of overlapping and closing the overlapping portions in the vicinity of the opening end, the corrugated base tube, and a method for manufacturing the corrugated tube It is.

  Conventionally, when laying an electric wire or the like, the electric wire or the like is inserted into a protective tube such as a corrugated tube. Since the corrugated tube is tubular, in order to insert the electric wire into such a tubular member, it is necessary to sequentially feed the electric wire from the end. However, this work has not always been easy.

  On the other hand, there is a method in which a part of the corrugated tube is cut along the longitudinal direction and an electric wire is inserted from the cut. In this case, workability is good because there is no need to feed the electric wires in the longitudinal direction.

  When using such a corrugated pipe having an opening, in order to prevent the electric wire inserted from the opening from being exposed and damaged, after inserting the electric wire into the corrugated pipe, tape is applied to the corrugated pipe. It is necessary to prevent the electric wire from being exposed to the outside by winding. For this reason, cost reduction by simplification of work has been desired.

  Such a corrugated tube has, for example, an outer shell and an inner shell on both sides of the hinge portion, and when the two are fitted, the opening size of the outer shell is larger than that of the outer shell. There is a method of fitting a small inner shell into a corrugated tube (Patent Document 1).

  Patent Document 1 discloses that the outer shell expands to a position corresponding to the diameter of the outer shell when the inner shell is fitted to the outer shell by making the opening E1 of the outer shell smaller than the diameter D. After that, it returns to its original state from the expanded state.

  In addition, there is a corrugated tube that can be closed by overlapping the inner member and the outer member by bending the inner member and the outer member having openings facing each other via the hinge portion, and bending the hinge portion. This corrugated tube has a substantially oval cross section in which the opening dimension between the end portion of the inner member and the hinge portion is larger than the opening dimension of the outer member (Patent Document 2).

  In addition, the peak and valley portions formed in the tube axis direction are overlapped and fitted to both ends of the opening portion of the corrugated tube having openings at predetermined positions in the circumferential direction extending linearly in the tube axis direction. There is a corrugated tube in which the thickness of the overlapping portion is thinner than the portion other than the overlapping portion. Under the present circumstances, the transition part from the corrugated crest inner surface of the outer side wrap part to the crest side shows the maximum elongation, and the transition part from the corrugated inner surface of the inner wrap part to the crest side shows the minimum elongation. Also. The portion where the outer wrap portion transitions to the non-wrap portion has a larger axial extension than the corrugated portion of the non-wrap portion, and the portion where the inner portion of the wrap portion transitions to the non-wrap portion is the axial direction than the corrugated portion of the non-wrap portion Is small (Patent Document 3).

  Moreover, with respect to the corrugated pipe in which the corrugated pipe corresponding to Patent Document 3 overlaps in the radial direction, the corrugated pipe is opened by expanding the outer overlapping portion from the diameter at the time of molding, and the electric wire is inserted. There is a method of inserting an electric wire that is closed in a previous state (Patent Document 4).

Special table 2009-542180 gazette International Publication WO / 2015/099128 Special table 2001-509241 gazette Special table 2002-536215 gazette

  In Patent Document 1 and Patent Document 2, since the hinge portion for opening and closing the corrugated tube is provided, the strength in the circumferential direction of the tube cross section is not constant. For this reason, the deformation | transformation of the pipe cross section in a compressive load test when a converging electric wire is inserted in a bending deformation or a corrugated pipe is large. Moreover, since the electric wire can be easily inserted by opening and closing the hinge portion, the tube can be easily opened, so that there is a problem that the overlapping amount of the overlapping portion of the tube has to be increased.

  Moreover, although there exists the invention of the split corrugated pipe | tube which has the overlapping part which does not have a hinge part like patent document 3 and patent document 4, patent document 3 is thick in the peak part trough part of a corrugated pipe | tube. The tube itself is heavy and has a problem with bendability.

  The present invention has been made in view of such a problem, and it is possible to prevent an electric wire inserted from an opening from being exposed without providing a hinge portion, and is lightweight and excellent in bendability. An object of the present invention is to provide a corrugated tube, a corrugated base tube, and a method for manufacturing the corrugated tube.

  In order to achieve the above-mentioned object, the first invention is a corrugated pipe in which a plurality of crests and troughs extending in the circumferential direction are repeatedly formed in the pipe axis direction alternately at a predetermined interval. In the cross-section perpendicular to the longitudinal direction of the corrugated tube, the overlapping portions where the peak portions and the valley portions of the corrugated tube overlap each other at both ends in the circumferential direction of the corrugated tube, A corrugated tube having a curved connecting portion connecting the overlapping portions at both ends, and capable of closing the tube by overlapping the crests and the troughs of the overlapping portion. In a state where the corrugated tube is opened without overlapping parts, in the cross section perpendicular to the longitudinal direction of the corrugated tube, one of the overlapping portions is an inner overlapping portion, and the other overlapping portion An outer overlapping portion, the inner overlapping portion is disposed on the outer peripheral side of the outer overlapping portion, and when the curved connecting portion is reduced in diameter and closed, the peak portion of the inner overlapping portion and the The outer peripheral surface of the valley portion exerts an elastic repulsive force on the peak portion and the valley portion of the outer overlapping portion, and a part of the inner peripheral surface of the peak portion and the valley portion of the outer overlapping portion or The corrugated pipe is characterized in that the inner overlapping portion can be overlapped with the inner side of the outer overlapping portion so as to be in contact with the entire surface.

  In a state perpendicular to the longitudinal direction of the corrugated tube in a state where both ends in the circumferential direction of the corrugated tube are butted, the radius of curvature of the inner peripheral surface of the inner overlapping portion and the radius of curvature of the outer overlapping portion are In comparison, the curvature radius of the inner overlapping portion is larger than the curvature radius of the outer overlapping portion, and at least one of the center of curvature radius of the inner overlapping portion and the center of curvature radius of the outer overlapping portion is: You may arrange | position in the position offset from the center position of the said curve connection part.

  In this case, the center of the radius of curvature of the inner overlap portion may be arranged at a position offset from the center position of the curve connection portion toward the curve connection portion in the direction opposite to the inner overlap portion. The center of the radius of curvature of the outer overlapping portion may be arranged at a position offset from the center position of the curved connection portion toward the outer overlapping portion.

  When offsetting only one of the inner overlapping portion and the outer overlapping portion, it is desirable to offset only the outer overlapping portion from the viewpoint of shape control of the outer overlapping portion.

  In a state where both ends in the circumferential direction of the corrugated pipe are butted, the distance from the outer peripheral surface of the tip of the inner overlapping portion to the center position of the curved connecting portion is from the inner peripheral surface of the tip of the outer overlapping portion. It may be 2 to 10% larger than the distance to the center position of the curved connection portion.

  The boundary portion between the inner overlapping portion and the curved connection portion and the boundary portion between the outer overlapping portion and the curved connection portion have step portions with respect to the circumferential direction, respectively, and each of the boundary portions The outer peripheral surface of the peak portion of the inner overlapping portion is positioned inside the outer peripheral surface of the peak portion of the curved connection portion, and the inner peripheral surface of the valley portion of the outer overlapping portion is the curved connection. It may be formed outside the inner peripheral surface of the valley portion of the portion.

  It is desirable that the inner overlapped portion and the outer overlapped portion are thinner than the curved connecting portion.

  The step portion formed at the boundary portion between the inner overlapping portion and the curved connection portion includes a side wall of the peak portion sandwiching the valley portion from both sides on the outer peripheral surface of the valley portion of the inner overlapping portion. A wall is formed so as to connect to the stepped portion formed at the boundary portion between the outer overlap portion and the curved connection portion, on the inner peripheral surface of the mountain portion of the outer overlap portion. A wall may be formed so as to connect the side walls of the valley part sandwiching the mountain part from both sides.

  The thickness of the central portion in the circumferential direction of the curved connection portion is formed thinner than the thickness of both side portions sandwiching the central portion in the circumferential direction of the curved connection portion, or the thickness of the central portion in the circumferential direction of the curved connection portion The wall thickness may be formed such that the wall thickness gradually decreases from both sides of the central portion in the circumferential direction of the curved connection portion toward the central portion of the curved connection portion.

  The angle at which the inner overlap portion is formed in the circumferential direction with respect to the center of the curved connection portion is in the range of 35 ° to 65 °, and the angle at which the outer overlap portion is formed is from 35 ° to 35 °. It is a range of 65 °, and the formation length in the circumferential direction of the inner overlapping portion may be equal to or longer than the formation length of the outer overlapping portion.

  When the inner overlapping portion and the outer overlapping portion are overlapped, the length of the inner overlapping portion that is not overlapped and is exposed is 1/3 of the circumferential length of the inner overlapping portion. The following ranges may be used.

  As the width of the inner peripheral surface of the crest portion of the outer overlapping portion gradually increases toward the base portion of the crest portion, the outer periphery of the crest portion of the inner overlapping portion that is further widened and fitted therein The width of the surface is formed narrower than the width of the inner peripheral surface of the peak portion of the outer overlap portion, and the outer overlap portion is overlapped with the outer overlap portion and the inner overlap portion. The width of the inner peripheral surface of the peak portion of the outer overlapping portion between the inner peripheral surface of the peak portion and the outer peripheral surface of the peak portion of the inner overlapping portion is 10 on one side. It may have a clearance in the range of ~ 20%.

  The height of the outer peripheral surface of the peak portion of the inner overlapping portion is lower than the height of the inner peripheral surface of the peak portion of the outer overlapping portion, and the outer overlapping portion and the inner overlapping portion are overlapped. When combined, the height of the crest portion of the outer overlap portion is between the inner peripheral surface of the crest portion of the outer overlap portion and the outer peripheral surface of the crest portion of the inner overlap portion. You may have clearance of the range of 10-20% with respect to the height of an internal peripheral surface.

  The thickness of the top portion of each of the peak portions of the inner overlapping portion and the outer overlapping portion is smaller than the thickness of the curved connection portion, and the total thickness of the inner overlapping portion and the outer overlapping portion. The value may be larger than the wall thickness of the curved connection part.

  The corrugated pipe is torsionally deformed in a circumferential direction, and the crest and trough of the inner overlapping section are longer than the crest and trough of the outer overlapping section. The overlapped portions may be formed by being twisted with respect to the tube axis direction.

  The corrugated tube may be bent.

  The overlap portion is formed with a rib that connects the peak portions in the tube axis direction along the tube axis direction, and the rib formed in the valley portion of the inner overlap portion is the outer overlap portion. When the inner overlapping portion and the outer overlapping portion are overlapped with each other, the rib of the inner overlapping portion is formed on the outer side when the inner overlapping portion and the outer overlapping portion are overlapped. It may be possible to fix the overlapping portion by being accommodated in the rib of the overlapping portion.

  The ribs may be formed intermittently at predetermined intervals in the axial direction of the corrugated pipe.

  According to the first invention, in the state in which the corrugated tube is opened without overlapping the overlapping portion, the inner overlapping portion is arranged on the outer peripheral side from the outer overlapping portion, so the diameter of the curved connecting portion is reduced. When the tube is closed, the outer peripheral surface of the inner overlapping portion exerts an elastic repulsive force on the outer overlapping portion. For this reason, the state which the corrugated pipe | tube closed is reliably maintained, and an internal electric wire etc. are not exposed outside.

  Further, by making the curvature radius of the inner overlapping portion larger than the curvature radius of the outer overlapping portion, when the two overlapping portions are overlapped, the inner overlapping portion becomes the outer overlapping portion having a smaller curvature radius. It is expanded and an elastic repulsive force is exerted on the outer overlapping portion so that the curvature radii of both are equal or the difference in curvature radii is reduced. For this reason, the state which the corrugated pipe | tube closed with maintaining a suitable contact pressure mutually can be maintained reliably.

  In particular, such an effect can be obtained more reliably by arranging the center of the radius of curvature of at least one of the inner overlapping portion and the outer overlapping portion at a position offset from the center position of the curved connecting portion. it can. Moreover, by doing in this way, an inner side overlapping part or an outer side overlapping part and a curve connection part can be gently connected by the curve. For this reason, it is possible to prevent unnecessary distortion from being formed on the outer peripheral surface of the outer overlapping portion and the curved connection portion and on the inner peripheral surface of the inner overlapping portion and the curved connection portion.

  Further, the distance from the outer peripheral surface of the tip of the inner overlapping portion to the center position of the curved connection portion is made 2 to 10% larger than the distance from the inner peripheral surface of the tip of the outer overlapping portion to the central position of the curved connection portion. Thereby, the effect mentioned above can be acquired more reliably. In particular, by setting the difference between the distances in such a range, it is possible to reliably obtain an elastic repulsive force and to easily overlap the overlapping portions.

  In addition, by providing a step at the boundary between each overlapping portion and the curved connection portion, it is possible to prevent the overlapping portion from entering the curved connection portion in the circumferential direction.

  In addition, the thickness of the inner and outer overlapping parts is made thinner than the thickness of the curved connection part to prevent the total thickness from becoming too thick when both overlapping parts are stacked. can do. For this reason, the bendability at the time of a bending process of a corrugated pipe can be improved.

  In addition, by forming a wall so as to connect the side wall sandwiching the valley portion of the inner overlapping portion from both sides to the step portion formed at the boundary portion between the inner overlapping portion and the curved connection portion, the curve of the overlapping portion is obtained. It is possible to more reliably prevent the circumferential portion from entering the connecting portion. Similarly, by forming a wall so as to connect the side wall sandwiching the crest portion of the outer overlapping portion from both sides to the step portion formed at the boundary portion between the outer overlapping portion and the curved connection portion, It is possible to more reliably prevent the circumferential connection of the curved connecting portion.

  Further, by forming the thickness of the central portion of the curved connection portion thinner than the thickness of both side portions of the central portion excluding the central portion of the curved connection portion, the curved connection portion can be easily bent. For this reason, an overlapping part becomes easy to overlap and it can prevent a mouth opening. At this time, it is possible to suppress a sudden change in the thickness in the circumferential direction by forming the thickness so that the thickness gradually decreases from both sides of the central portion of the curved connection portion toward the central portion of the curved connection portion. it can.

  Moreover, the opening of the overlapping portion in the circumferential direction can be prevented by forming the length of the overlapping portion at a predetermined angle or more. Furthermore, by forming the length of the overlapping portion in the circumferential direction to be equal to or less than a predetermined angle, the overlapping of the inner overlapping portion and the outer overlapping portion can be facilitated.

  In addition, when the inner overlapping portion and the outer overlapping portion are overlapped, the overlapping length that allows the exposure of the inner overlapping portion is set to 1/3 or less of the circumferential length of the inner overlapping portion. The overlapping length between the inner overlapping portion and the outer overlapping portion is sufficiently ensured, and the material is not wasted.

  In addition, by forming a predetermined clearance in the width direction of the crests and troughs of the inner and outer overlapping parts, the corrugated pipe can be deformed in the crests and troughs during bending. Can be partially absorbed. For this reason, it is difficult for the corrugated pipes to overlap.

  Similarly, by forming a predetermined clearance in the height direction of the crests and troughs of the inner overlapping part and the outer overlapping part, the corrugated pipe crests and troughs can be deformed when the corrugated pipe is bent. Some can be absorbed by the clearance. For this reason, it is difficult for the corrugated pipes to overlap.

  In addition, by making the thickness of each of the inner overlapping portion and the outer overlapping portion thinner than the thickness of the curved connecting portion, the thickness of the overlapping portion of the inner overlapping portion and the outer overlapping portion does not become too thick. The corrugated tube can be prevented from becoming difficult to bend. In addition, by ensuring that the total thickness of the inner overlapping portion and the outer overlapping portion is larger than the thickness of the curved connection portion, sufficient strength is ensured in the overlapping portion of the inner overlapping portion and the outer overlapping portion. Can do.

  In addition, the corrugated pipe is formed by fitting the crests and troughs of the inner overlapping part to the crests and troughs of the outer overlapping part with a predetermined pitch shift in the longitudinal direction of the corrugated pipe. The tube can be closed by being twisted in the circumferential direction. By doing in this way, the opening part of a corrugated pipe can be arrange | positioned diagonally with respect to a pipe-axis direction, and also a shearing force can be provided in the direction which prevents the opening of a corrugated pipe.

  Further, such twisting of the corrugated tube is particularly effective when the corrugated tube is bent. Since the overlapped portion has a predetermined angle with the tube axis direction, it is possible to avoid placing only the end of the overlapped portion in the portion where the bending distortion during bending is large, and the corrugated tube is not overlapped. hard.

  Moreover, when the inner overlapping portion and the outer overlapping portion are overlapped, the ribs are fitted to each other by forming ribs on the inner overlapping portion and the outer overlapping portion, respectively. Can do. For this reason, the opening of the corrugated tube can be prevented more reliably.

  At this time, the bendability of the corrugated tube can be improved by forming the ribs intermittently at predetermined intervals in the axial direction of the corrugated tube.

  A second invention is a corrugated element tube in which crests and troughs extending in the circumferential direction are repeatedly formed in a tube axis direction alternately at a predetermined interval, and a cross section perpendicular to the longitudinal direction of the corrugated element tube In the circumferential direction of the corrugated pipe, the ridges and valleys of the corrugated pipe are overlapped with each other, the curved connection part connecting the overlapping parts at both ends, A cross-section perpendicular to the longitudinal direction of the corrugated tube, one of the overlapping portions is an inner overlapping portion, and the other overlapping portion is an outer overlapping portion. The inner overlapping portion is arranged on the outer peripheral side of the outer overlapping portion, and the curvature radius of the inner peripheral surface of the inner overlapping portion is compared with the curvature radius of the outer overlapping portion. The radius of curvature of the inner overlapping portion is larger than the radius of curvature of the outer overlapping portion, and the center of the radius of curvature of the inner overlapping portion is opposite to the inner overlapping portion from the center of the curve connecting portion. Arranged at a position offset to the curve connection part side, or arranged at a position where the center of the radius of curvature of the outer overlap part is offset from the center position of the curve connection part to the outer overlap part side. It is a corrugated pipe characterized by being at least one of the above.

  When offsetting only one of the inner overlapping portion and the outer overlapping portion, the outer overlapping may be performed by matching the inner overlapping portion with the center of the curve connecting portion and offsetting only the center of the outer overlapping portion. This is desirable in terms of shape control.

  The distance from the outer peripheral surface at the tip of the inner overlapping portion to the center position of the curved connection portion is 2 to 10% from the distance from the inner peripheral surface of the tip of the outer overlapping portion to the central position of the curved connection portion. Larger is desirable.

  According to the second invention, it is possible to obtain a corrugated element tube with good manufacturability.

  3rd invention is the manufacturing method of the corrugated pipe | tube using the corrugated pipe | tube concerning 2nd invention, Comprising: The corrugated pipe | tube which has an opening part by cut | disconnecting the said connection part of the said corrugated pipe | tube, The corrugated tube is a method for manufacturing a corrugated tube, wherein the curved connecting portion can be reduced in diameter and the inner overlapping portion can be overlapped inside the outer overlapping portion to be closed.

  When the curved connecting portion is reduced in diameter and closed, the outer peripheral surfaces of the crest and trough of the inner overlapping portion are elastically repelled with respect to the crest and trough of the outer overlapping portion. The inner overlapping portion may be overlapped with the inner side of the outer overlapping portion so that the inner overlapping portion is in contact with a part or all of the inner peripheral surface of the peak portion and the valley portion of the outer overlapping portion. Good.

  According to the third invention, the corrugated pipe according to the first invention can be easily obtained.

  In addition, when the curved connecting portion is reduced in diameter and closed, the outer peripheral surface of the inner overlapping portion exerts an elastic repulsive force on the outer overlapping portion, thereby reliably maintaining the closed state, Internal wires are not exposed to the outside.

  ADVANTAGE OF THE INVENTION According to this invention, while being able to prevent the electric wire inserted from the opening part from being exposed, without providing a hinge part, while being lightweight, it is the corrugated pipe | tube, corrugated base pipe, and corrugated pipe | tube excellent in bendability The manufacturing method of can be provided.

The top view which shows the corrugated pipe | tube 1 of the open state. It is sectional drawing which shows the corrugated pipe | tube 1, (a) is the sectional view on the AA line of FIG. 1, (b) is the I section enlarged view of (a). It is sectional drawing which shows the corrugated pipe | tube 1, and is the BB sectional drawing of FIG. It is sectional drawing which shows the corrugated pipe | tube 1, and is the BB sectional drawing of FIG. It is sectional drawing which shows the corrugated pipe | tube 1, and is the BB sectional drawing of FIG. It is sectional drawing which shows the corrugated pipe | tube 1, (a) is DD sectional view taken on the line of Fig.2 (a), (b) is CC sectional view taken on the line of Fig.2 (a). The top view which shows the corrugated pipe | tube 1 of the closed state. It is sectional drawing which shows the corrugated pipe 1, and is the KK sectional view taken on the line of FIG. It is sectional drawing which shows the corrugated pipe | tube 1, (a) is the LL sectional view taken on the line of FIG. 8, (b) is the M section enlarged view of (a). The top view which shows the corrugated pipe 1a of the open state. It is sectional drawing which shows the corrugated pipe 1a, (a) is the RR sectional view taken on the line of FIG. 10, (b) is a figure which shows the state which closed the corrugated pipe 1a of (a). It is sectional drawing which shows the corrugated pipe 1a, (a) is the SS sectional view taken on the line of FIG. 10, (b) is the figure which shows the state which closed the corrugated pipe 1a of (a). The top view which shows the corrugated pipe 1b of the open state. It is sectional drawing which shows the corrugated pipe 1b, (a) is the VV sectional view taken on the line of FIG. 13, (b) is the figure which shows the state which closed the corrugated pipe 1b of (a). The top view which shows the corrugated pipe 1c of the open state. The top view which shows the corrugated pipe 1d of the open state. (A) is a top view which shows corrugated pipe 1 of the open state, (b) is a top view which shows the other form of corrugated pipe 1 of the closed state. The figure which shows the state which bent the corrugated pipe. (A) is sectional drawing which shows the corrugated base tube 20, (b) is sectional drawing which shows the corrugated pipe 1. FIG.

(First embodiment)
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a plan view showing a corrugated tube 1, FIG. 2 (a) is a cross-sectional view taken along the line AA of FIG. 1 (a cross-sectional view perpendicular to the longitudinal direction of the corrugated tube 1), and FIGS. FIG. 2 is a cross-sectional view taken along the line BB in FIG. 1 (a cross-sectional view perpendicular to the longitudinal direction of the corrugated tube 1). 1 to 5 show a state where the corrugated tube 1 is opened (a state where the tube is not closed). Details of the closed state of the tube will be described later.

  In the corrugated tube 1, a plurality of crests 3 and troughs 5 extending in the circumferential direction are repeatedly formed alternately in the tube axis direction at predetermined intervals. In the following description, the convex portion on the outer surface side of the corrugated tube 1 is referred to as a peak portion 3, and the concave portion on the outer surface side of the corrugated tube 1 is referred to as a valley portion 5. Therefore, the convex portion on the inner surface side of the corrugated tube 1 is the inner surface side of the valley portion 5, and the concave portion on the inner surface side of the corrugated tube 1 is the inner surface side of the peak portion 3.

  The corrugated pipe 1 has an opening 11 in a pipe circumferential cross section. That is, the opening 11 is formed continuously in the tube axis direction of the corrugated tube 1. Further, in the cross section perpendicular to the longitudinal direction of the corrugated tube, overlapping portions 7 where the crest portions 3 and the trough portions 5 of the corrugated tube 1 overlap each other are provided at both ends in the circumferential direction of the corrugated tube 1. One end portion side of the overlapping portion 7 is the inner overlapping portion 7a, and the other end portion side is the outer overlapping portion 7b.

  A curved connection portion 9 is formed between the inner overlapping portion 7a and the outer overlapping portion 7b of the corrugated tube 1. That is, the curve connecting portion 9 is a portion that connects the inner overlapping portion 7a and the outer overlapping portion 7b.

  6A is a cross-sectional view taken along line DD in FIG. 2, and FIG. 6B is a cross-sectional view taken along line CC in FIG. 6A is a cross-sectional view of the outer overlapping portion 7b (a cross-sectional view in the longitudinal direction of the corrugated tube 1), and FIG. 6B is a cross-sectional view of the inner overlapping portion 7a (the corrugated tube 1). FIG.

  As described above, the crests 3 and the troughs 5 are alternately and repeatedly formed in each overlapping portion. In addition, the inner surface dimension of the peak part 3 of the outer overlapping part 7b is larger than the outer surface dimension of the peak part 3 of the inner overlapping part 7a. In addition, the inner surface dimension of the valley portion 5 of the outer overlapping portion 7b is smaller than the outer surface dimension of the valley portion 5 of the inner overlapping portion 7a.

  Therefore, the corrugated pipe 1 can reduce the diameter of the curved connecting portion 9 and can overlap the crest portions 3 and the trough portions 5 of the inner overlapping portion 7a and the outer overlapping portion 7b. By doing in this way, it is possible to close the corrugated pipe 1.

  Here, the thickness (t2 in FIG. 2) of the crest 3 of the inner overlapping portion 7a and the thickness (t3 in FIG. 2) of the crest 3 of the outer overlapping portion 7b are the curved connecting portion 9. It is desirable that the thickness be smaller than the thickness (t1 in FIG. 2) of the top of the crest 3. In the following description, the thickness of each part is the thickness at the top of the peak part 3 unless otherwise specified.

  By doing in this way, when the inner overlapping part 7a and the outer overlapping part 7b are overlapped, it is possible to suppress the thickness of the overlapping part from becoming too thick. Accordingly, the bendability of the corrugated tube 1 during bending can be improved by reducing the total thickness of the overlapping portion of the inner overlapping portion 7a and the outer overlapping portion 7b.

  The wall thicknesses t2 and t3 of the inner overlapping portion 7a and the outer overlapping portion 7b are smaller than the wall thickness t1 of the curve connecting portion 9, and the thickness t2 of the inner overlapping portion 7a and the outer overlapping portion 7b It is desirable that the total value (t2 + t3) of the wall thickness t3 is larger than the wall thickness t1 of the curve connecting portion 9.

  If the total thickness (t2 + t3) of the inner overlapping portion 7a and the outer overlapping portion 7b is too thicker than the thickness t1 of the other curved connection portions 9, the bendability of the corrugated pipe 1 is lowered. For example, if the total thickness (t2 + t3) of the overlapping portion is too thick, the corrugated tube 1 may be flattened when the corrugated tube 1 is bent. On the other hand, if the total thickness (t2 + t3) of the inner overlapping portion 7a and the outer overlapping portion 7b is too thin, the tensile strength of the corrugated tube 1 may be insufficient. For this reason, it is desirable that t2, t3 <t1 <t2 + t3.

  Here, FIG.2 (b) is the I section enlarged view of Fig.2 (a). The thickness of the central portion in the circumferential direction of the curved connection portion 9 (t4 in FIG. 2B) is the thickness of both side portions sandwiching the central portion in the circumferential direction of the curved connection portion 9 (t1 in FIG. 2B). It is desirable to form it thinner. For example, the thickness (t4 in FIG. 2B) of the central portion in the circumferential direction of the curved connection portion 9 gradually increases from both sides of the central portion in the circumferential direction of the curved connection portion 9 toward the central portion of the curved connection portion 9. It is desirable that the thickness be reduced.

  By doing in this way, the curve connection part 9 can be made easy to reduce in diameter. For this reason, the inner overlapping portion 7a and the outer overlapping portion 7b can be easily overlapped, and the mouth opening can be prevented. In addition, by forming the thickness so that the thickness gradually decreases toward the central portion of the curved connection portion 9, it is possible to prevent a sudden thickness change portion from being formed in the curved connection portion 9.

  In a state where the end portions of the inner overlapping portion 7a and the outer overlapping portion 7b are abutted with each other without closing the corrugated tube 1, the inner overlapping portion 7a is disposed on the outer peripheral side from the outer overlapping portion 7b. That is, as shown in FIG. 3, when the center position of the curve connecting portion 9 is O1, the end portions of the inner overlapping portion 7a and the outer overlapping portion 7b are joined to each other at the abutting portion from the center position O1 to the inner overlapping portion 7a. Is longer than the distance from the center position O1 to the inner surface of the outer overlapping portion 7b. By doing so, as will be described later, when the inner overlapping portion 7a and the outer overlapping portion 7b are overlapped, the elastic repulsion force on the outer overlapping portion 7b on the outer peripheral surface of the inner overlapping portion 7a. Can affect.

  More specifically, the distance T from the outer peripheral surface of the tip of the inner overlapping portion 7a to the center position O1 of the curve connecting portion 9 in a state where both ends in the circumferential direction of the corrugated tube 1 are abutted is the outer overlapping portion. It is desirable that it is 2 to 10% larger than the distance U from the inner peripheral surface of the tip of 7b to the center position O1 of the curved connection part 9. That is, it is desirable that T = U × 1.02 to 1.1.

  When the ratio of the distance between the two is smaller than 2%, when the inner overlapping portion 7a and the outer overlapping portion 7b are overlapped, the outer peripheral surface of the inner overlapping portion 7a is sufficient with respect to the outer overlapping portion 7b. An elastic repulsion cannot be applied. On the other hand, if the ratio of the distance between the two is greater than 10%, it is difficult to overlap the inner overlapping portion 7a with the outer overlapping portion 7b. In addition, if the ratio of the distance between the two is too large, when the inner overlapping portion 7a and the outer overlapping portion 7b are overlapped, there is a possibility that the overlapping portion will be shifted or opened due to the excessively large elastic repulsion force. . For this reason, it is desirable that the ratio of the distance between the two is in the range of 2 to 10%.

  Further, in a state where both ends in the circumferential direction of the corrugated tube 1 are butted, the radius of curvature of the inner circumferential surface of the inner overlapping portion 7a (R1 in FIG. 4) and the radius of curvature of the outer overlapping portion 7b (R2 in FIG. 4). ) Is larger than the curvature radius R2 of the inner overlapping portion 7b.

  Further, the center O2 of the curvature radius R2 of the outer overlapping portion 7b is disposed at a position offset from the center position O1 of the curve connecting portion 9. More specifically, as shown in FIG. 4, the center O2 of the radius of curvature R2 of the outer overlapping portion 7b is disposed at a position offset from the center position O1 of the curve connecting portion 9 toward the outer overlapping portion 7b. The Further, the center O3 of the radius of curvature R1 of the inner overlapping portion 7a is disposed at a position offset from the center O1 of the curved connecting portion 9 to the curved connecting portion 9 side opposite to the inner overlapping portion 7a side.

  In this way, when the inner overlapping portion 7a is overlapped with the outer overlapping portion 7b, the inner overlapping portion 7a disposed on the inner side becomes the outer overlapping portion 7b having a small curvature radius located on the outer periphery thereof. Abut to expand. For this reason, an elastic repulsive force can be generated so that both curvature radii may become equal. Further, the inner overlapping portion 7a and the outer overlapping portion 7b can be smoothly connected to the curved connection portion 9. For this reason, unnecessary distortion or the like is formed on the outer peripheral surface of the boundary portion between the outer overlapping portion 7b and the curved connection portion 9 and the inner peripheral surface of the boundary portion between the inner overlapping portion 7a and the curved connection portion 9. There is no.

  Here, a step portion 13 a is provided in the circumferential direction on the outer peripheral surface of the boundary portion between the inner overlapping portion 7 a and the curved connection portion 9. Due to the stepped portion 13 a, the outer peripheral surface of the peak portion 3 of the inner overlapping portion 7 a is positioned inside the outer peripheral surface of the peak portion 3 of the curved connection portion 9. That is, in the vicinity of the boundary between the inner overlapping portion 7a and the curved connecting portion 9, the distance from the center O1 of the curved connecting portion 9 to the outer peripheral surface of the peak portion 3 of the inner overlapping portion 7a (E in FIG. 5). The distance (F in FIG. 5) from the center O1 of the curve connection portion 9 to the outer peripheral surface of the peak portion 3 of the curve connection portion 9 is larger.

  Similarly, a step portion 13b is provided in the circumferential direction on the inner peripheral surface of the boundary portion between the outer overlapping portion 7b and the curve connecting portion 9. Due to the stepped portion 13 b, the inner peripheral surface of the valley portion 5 of the outer overlapping portion 7 b is positioned outside the inner peripheral surface of the valley portion 5 of the curved connection portion 9. That is, in the vicinity of the boundary between the outer overlapping portion 7b and the curved connecting portion 9, the distance from the center O1 of the curved connecting portion 9 to the inner peripheral surface of the valley portion 5 of the outer overlapping portion 7b (H in FIG. 5). However, the distance (G in FIG. 5) from the center O1 of the curve connection portion 9 to the inner peripheral surface of the valley portion 5 of the curve connection portion 9 is smaller.

  Thus, by providing the inner overlapping portion 7a and the curved connecting portion 9 with the step portions 13a and 13b, the inner overlapping portion 7a and the curved connecting portion are overlapped when the inner overlapping portion 7a and the outer overlapping portion 7b are overlapped. It is possible to prevent 9 from entering the curved connection portion 9 in the circumferential direction. The overlapping state of the inner overlapping portion 7a and the curve connecting portion 9 will be described later in detail.

  The angle (θ1 in FIG. 5) at which the inner overlapping portion 7a is formed in the circumferential direction with respect to the center O1 of the curved connection portion 9 is preferably in the range of 35 ° to 65 °. Similarly, the angle (θ2 in FIG. 5) at which the outer overlapping portion 7b is formed with respect to the center O1 of the curved connection portion 9 is desirably in the range of 35 ° to 65 °. More desirably, the angle is 35 ° to 60 °.

  Thus, by forming the circumferential length of the inner overlapping portion 7a and the outer overlapping portion 7b at an angle of 35 ° or more, the circumferential length of the inner overlapping portion 7a and the outer overlapping portion 7b is increased. Sufficient allowance can be secured. For this reason, it is possible to prevent opening of the corrugated tube 1 during bending.

  Further, when the corrugated tube 1 is shifted from the open tube state to the closed tube state, the diameter of the curved connecting portion 9 is reduced. However, if the overlapping length of the inner overlapping portion 7a and the outer overlapping portion 7b is long, The amount of diameter reduction at the time of matching increases. On the other hand, the inner overlapping portion 7a and the outer overlapping portion 7b can be easily overlapped by forming the circumferential length of the inner overlapping portion 7a and the outer overlapping portion 7b at an angle of 65 ° or less. It becomes. If the circumferential length of the inner overlapping portion 7a and the outer overlapping portion 7b exceeds 65 °, the amount of diameter reduction at the time of overlapping becomes too large, making it difficult to reduce the diameter, and the shape after the diameter reduction is not good. It tends to be stable.

  The formation length of the inner overlapping portion 7b in the circumferential direction is desirably equal to or longer than the formation length of the outer overlapping portion 7b.

  Next, a state where the corrugated pipe 1 is closed will be described. 7 is a plan view showing the corrugated tube 1 in a closed state, and FIG. 8 is a cross-sectional view taken along the line KK of FIG. 7 (a cross section perpendicular to the longitudinal direction of the corrugated tube 1).

  As shown in the drawing, by reducing the diameter of the curved connecting portion 9, the inner overlapping portion 7a can be overlapped with each other so as to be inside the outer overlapping portion 7b (in the direction of arrow J in the figure). At this time, the peak portions 3 and the valley portions 5 of the inner overlapping portion 7a and the outer overlapping portion 7b are overlapped. By doing in this way, the corrugated pipe | tube 1 can be closed.

  For example, in a state where the corrugated tube 1 is opened, an electric wire or the like is accommodated in the corrugated tube 1 from the opening 11. At this time, since an electric wire or the like can be inserted from the opening 11, it is not necessary to feed the electric wire or the like from the end of the corrugated tube 1 over the entire length. After that, by closing the corrugated tube 1 as described above, it is possible to reliably protect the wires and the like without exposing the wires and the like to the outside.

  When the corrugated tube 1 is closed, the inner overlapping portion 7a is in contact with part or all of the inner peripheral surfaces of the crest 3 and trough 5 of the outer overlapping portion 7b. 7b is superimposed on the inside. As described above, when the corrugated pipe 1 is closed by reducing the diameter of the curved connecting portion 9, the outer peripheral surfaces of the peak portion 3 and the valley portion 5 of the inner overlapping portion 7a are connected to the peak portion 3 of the outer overlapping portion 7b. An elastic repulsion force is exerted on the valley portion 5.

  Note that the entire range of the inner overlapping portion 7a and the outer overlapping portion 7b may not overlap completely. However, when the inner overlapping portion 7a and the outer overlapping portion 7b are overlapped, the length that the inner overlapping portion 7a is exposed to the outer surface without being overlapped is the circumferential length of the inner overlapping portion 7b. It is desirable that it is 1/3 or less.

  When the length at which the inner overlapping portion 7a is exposed to the outer surface becomes 1/3 or more of the length of the inner overlapping portion 7a, the overlapping length between the inner overlapping portion 7a and the outer overlapping portion 7b is insufficient. For this reason, the fitting between the inner overlapping portion 7a and the outer overlapping portion 7b becomes insufficient, and the overlapping portion may be opened, and the material is also wasted.

  9A is a cross-sectional view taken along the line LL in FIG. 8 (circumferential cross-section of the corrugated tube 1), and FIG. 9B is an enlarged view of a portion M in FIG. 9A. As described above, when the corrugated tube 1 is closed, the peak portions 3 and the valley portions 5 of the inner overlapping portion 7a and the outer overlapping portion 7b are overlapped.

  Here, the width of the inner peripheral surface of each crest 3 of the inner overlap portion 7a and the outer overlap portion 7b gradually widens toward the base portion (the valley portion 5 side) of the crest 3. . Further, the width of the outer peripheral surface of the peak portion 3 of the inner overlapping portion 7a that fits the peak portion 3 of the outer overlapping portion 7b is narrower than the width of the inner peripheral surface of the peak portion 3 of the outer overlapping portion 7b. It is formed.

  More specifically, when the outer overlapping portion 7b and the inner overlapping portion 7a are overlapped, the width of the inner peripheral surface of the crest 3 of the outer overlapping portion 7b (N in FIG. 9B) is The width of the outer peripheral surface of the crest portion 3 of the inner overlapping portion 7a is smaller than (O in FIG. 9B). Further, 10% to 20% on one side (width N) between the inner peripheral surface of the crest 3 of the outer overlapping portion 7b and the outer peripheral surface of the crest 3 of the inner overlapping portion 7a with respect to the width direction at an arbitrary position. Clearance) is formed. That is, O = N × 0.6 to 0.8 is set.

  Further, the height of the outer peripheral surface of the crest 3 of the inner overlapping portion 7a (Q in FIG. 9B) is the height of the inner peripheral surface of the crest 3 of the outer overlapping portion 7b (FIG. 9B). P). Further, when the outer overlapping portion 7b and the inner overlapping portion 7a are overlapped, the height between the inner peripheral surface of the peak portion 3 of the outer overlapping portion 7b and the outer peripheral surface of the peak portion 3 of the inner overlapping portion 7a. During the vertical direction, a clearance in the range of 10 to 20% is formed with respect to the height P of the inner peripheral surface of the crest 3 of the outer overlapping portion 7b. That is, Q = P × 0.8 to 0.9.

  Here, when the corrugated tube 1 is bent, the peak portion 3 and the valley portion 5 of the corrugated tube 1 are deformed, and as a result, the corrugated tube 1 is locally deformed in the tube axis direction. On the other hand, by providing clearances in the fitting portions of the crests 3 and troughs 5 of the outer overlapping portion 7b and the inner overlapping portion 7a, the above expansion and contraction can be partially absorbed by the clearance. For this reason, the overlapping portion of the outer overlapping portion 7b and the inner overlapping portion 7a is difficult to come off. Moreover, if clearance is enough, the peak parts 3 and the trough parts 5 can be reliably fitted.

  In addition, in order to maintain the closed state of the corrugated pipe 1 more reliably, the corrugated pipe 1 may be heat-treated. For example, when the corrugated pipe 1 is made of a thermoplastic resin, the corrugated pipe 1 can be stably maintained in a desired shape by heating the corrugated pipe 1.

  In this case, after the corrugated tube 1 is heated to a predetermined temperature, the corrugated tube 1 may be formed into a closed tube shape, or the corrugated tube 1 may be formed into a closed tube shape while being heated to a predetermined temperature. You may heat to predetermined temperature after hold | maintaining. Further, the corrugated tube 1 can be processed into a closed tube shape by holding it in a batch mold and forming it, or by any method such as roll processing in a heating oven. The thermoplastic resin is preferably PP (polypropylene) or PA (polyamide) from the viewpoints of moldability and cost. Other thermoplastic resins can also be used as appropriate.

  As mentioned above, according to this Embodiment, since the corrugated pipe 1 does not have a hinge part, the intensity | strength of the circumferential direction of a pipe cross section can be made substantially constant. For this reason, the bending deformation of the corrugated pipe 1 and the deformation of the pipe cross section in the compression load resistance test in which the converging wire is inserted inside the corrugated pipe can be suppressed.

  Further, in a state where the corrugated tube 1 is opened, the inner overlapping portion 7a is located outside the outer overlapping portion 7b. For this reason, when the corrugated tube 1 is closed, an elastic repulsive force can be generated and brought into contact with the outer overlapping portion 7b by the inner overlapping portion 7a. For this reason, the corrugated pipe 1 can be closed reliably and the opening of the corrugated pipe 1 can be suppressed.

  In particular, the distance from the outer peripheral surface at the tip of the inner overlapping portion 7a to the center position O1 of the curve connecting portion 9 is greater than the distance from the inner peripheral surface at the tip of the outer overlapping portion 7b to the center position O1 of the curved connecting portion 9. By increasing the size by 2 to 10%, it is possible to improve the workability of the overlapping of the inner overlapping portion 7a and the outer overlapping portion 7b, and it is possible to prevent opening when both are overlapped. .

  In addition, by offsetting the center of at least one of the inner overlapping portion 7a and the outer overlapping portion 7b from the center of the curved connecting portion 9, the outer surfaces of the outer overlapping portion 7b and the curved connecting portion 9 are smoothly connected. A corrugated tube 1 having a shape can be obtained. Therefore, no distortion or the like is formed on the outer surface of the outer overlapping portion 7b and the curved connecting portion 9 or the inner surface of the inner overlapping portion 7a and the curved connecting portion 9, and the outer surface of the corrugated tube 1 is prevented from being damaged during handling. be able to.

  Further, a step portion 13 a is provided at the boundary portion between the inner overlapping portion 7 a and the curved connection portion 9, and a step portion 13 b is provided at the boundary portion between the outer overlapping portion 7 b and the curved connection portion 9. For this reason, when the inner overlapping portion 7a and the outer overlapping portion 7b are overlapped, the inner overlapping portion 7a and the outer overlapping portion 7b are prevented from entering the curve connecting portion 9 side beyond the overlapping portion. can do.

  Further, when the inner overlapping portion 7a and the outer overlapping portion 7b are overlapped, the length that the inner overlapping portion 7a is exposed without being overlapped is 1 of the circumferential length of the inner overlapping portion 7a. By setting the range to / 3 or less, a sufficient overlay length can be ensured.

  Further, by making the thickness of the inner overlapping portion 7a and the outer overlapping portion 7b thinner than the thickness of the curved connection portion 9, it is possible to suppress the total thickness of the overlapping portion from becoming too thick. be able to. For this reason, it can suppress that the bendability of the corrugated pipe 1 deteriorates.

  At this time, by making the total thickness of the inner overlapping portion 7 a and the outer overlapping portion 7 b larger than the thickness of the curved connection portion 9, sufficient tensile strength of the corrugated pipe 1 can be ensured.

  In addition, by forming the circumferential lengths of the inner overlapping portion 7a and the outer overlapping portion 7b at a predetermined angle or more, a sufficient overlapping margin can be secured, and the corrugated tube 1 can be bent. Open mouth can be prevented. In addition, by forming the circumferential length of the inner overlapping portion 7a and the outer overlapping portion 7b at a predetermined angle or less, the overlapping operation of the inner overlapping portion 7a and the outer overlapping portion 7b becomes easy. .

  Moreover, in the fitting part of each peak part 3 and trough part 5 of each of the outer overlapping part 7b and the inner overlapping part 7a, a clearance is provided in each of the width direction and the height direction, whereby the corrugated pipe 1 A part of the local expansion and contraction when bending can be absorbed. For this reason, the overlapping portions of the outer overlapping portion 7b and the inner overlapping portion 7a are unlikely to come off, and the mountain portions 3 and the valley portions 5 can be reliably fitted.

(Second Embodiment)
Next, a second embodiment will be described. FIG. 10 is a plan view of the corrugated tube 1a in an open state, and FIG. 11A is a cross-sectional view taken along the line RR of FIG. In the following description, components having the same functions as those of the first embodiment are denoted by the same reference numerals as in FIGS. 1 to 9, and redundant description is omitted.

  The corrugated tube 1a has substantially the same configuration as the corrugated tube 1, but differs in that a wall 15a is formed at a step portion 13a formed at the boundary portion between the inner overlapping portion 7a and the curved connecting portion 9. . The wall 15a is formed on the outer peripheral surface of the valley portion 5 of the inner overlapping portion 7a. Moreover, the wall 15a is formed so that the side wall of the peak part 3 which pinches | interposes the trough part 5 of the inner side overlapping part 7a from both sides may be connected.

  As shown in FIG. 11A, the wall 15 a is formed at a height from the base of the valley 5 to the top of the peak 3. That is, the wall 15a is formed on the outer surface side of the corrugated pipe 1a, partitions the inner overlapping portion 7a and the curved connection portion 9, and does not protrude outward from the peak portion 3. The wall 15a should just be formed in the moderate height which does not protrude from the peak part 3. FIG.

  FIG.11 (b) is a figure which shows the state which closed the corrugated pipe | tube 1a from the state of Fig.11 (a). As described above, when the corrugated tube 1a is closed, the outer overlapping portion 7b is overlapped on the outer side of the inner overlapping portion 7a. At this time, when the outer overlapping portion 7b is completely overlapped with the outer periphery of the inner overlapping portion 7a, the tip of the outer overlapping portion 7b contacts the wall 15a. For this reason, the outer overlapping portion 7b does not move further in the circumferential direction.

  In this way, by providing the wall 15a at the boundary between the inner overlapping portion 7a and the curve connecting portion 9, when the inner overlapping portion 7a and the outer overlapping portion 7b are overlapped, the outer overlapping portion 7b becomes the curved connecting portion. It is possible to prevent the outer surface of 9 from running in the circumferential direction.

  The arrangement of the walls is not limited to the example shown in FIG. FIG. 12A is a cross-sectional view taken along line S-S in FIG. As shown in FIG. 12A, a wall 15b may be formed on the step portion 13b formed at the boundary between the outer overlapping portion 7b and the curve connecting portion 9. The wall 15b is formed so as to connect the inner surface of the mountain portion 3 of the outer overlapping portion 7b to the inner surface of the side wall of the valley portion 5 sandwiching the inner surface of the mountain portion 3 from both sides.

  As shown in FIG. 12A, the wall 15 b is formed at a height from the top inner surface of the peak portion 3 to the inner surface of the valley portion 5. That is, the wall 15b is formed on the inner surface side of the corrugated pipe 1a, partitions the outer overlapping portion 7b and the curved connection portion 9, and does not protrude to the inner surface side from the valley portion 5.

  FIG.12 (b) is a figure which shows the state which closed the corrugated pipe | tube 1a from the state of Fig.12 (a). As described above, when the corrugated tube 1a is closed, the outer overlapping portion 7b is overlapped on the outer side of the inner overlapping portion 7a. At this time, when the outer overlapping portion 7b is completely overlapped with the outer periphery of the inner overlapping portion 7a, the tip of the inner overlapping portion 7b contacts the wall 15b. For this reason, the inner overlapping portion 7a does not move further in the circumferential direction.

  Thus, by providing the wall 15b at the boundary between the outer overlapping portion 7b and the curve connecting portion 9, when the inner overlapping portion 7a and the outer overlapping portion 7b are overlapped, the inner overlapping portion 7a becomes the curved connecting portion. It is possible to prevent the inner surface of 9 from running in the circumferential direction.

  The walls 15a and 15b may form both, but at least one of them may be formed.

  According to the second embodiment, an effect similar to that of the first embodiment can be obtained. Further, by forming the walls 15a and 15b at the step portions 13a and 13b, the inner overlapping portion 7a and the outer overlapping portion 7b are prevented from climbing onto the curved connection portion 9 when the corrugated tube 1 is closed. can do.

(Third embodiment)
Next, a third embodiment will be described. 13 is a plan view showing the corrugated tube 1b in an open state, and FIG. 14 (a) is a cross-sectional view taken along the line V-V in FIG. The corrugated tube 1b has substantially the same configuration as the corrugated tube 1, but differs in that ribs 17a and 17b are formed on the inner overlapping portion 7a and the outer overlapping portion 7b, respectively.

  The inner overlapping portion 7a is formed with a rib 17a that connects the mountain portions 3 in the tube axis direction along the tube axis direction. Similarly, the outer overlapping portion 7b is formed with a rib 17b that connects the crests 3 in the tube axis direction along the tube axis direction.

  The rib 17 a is formed at a height from the base of the valley 5 to the top of the peak 3. That is, the outer surface of the rib 17a does not protrude outward from the outer surface of the peak portion 3 of the inner overlapping portion 7a. Further, in the circumferential cross section, the width (circumferential length) of the inner circumferential surface of the rib 17a is gradually widened toward the base portion (the valley portion 5 side) of the rib 17a.

  Similarly, the rib 17 b is formed at a height from the base of the valley 5 to the top of the peak 3. That is, the outer surface of the rib 17b does not protrude outward from the outer surface of the peak portion 3 of the outer overlapping portion 7b. Further, in the circumferential cross section, the width (circumferential length) of the inner circumferential surface of the rib 17b gradually widens toward the base portion (the valley portion 5 side) of the rib 17b.

  The width of the outer peripheral surface of the rib 17a is narrower than the width of the inner peripheral surface of the rib 17b. That is, the rib 17a formed in the trough 5 of the inner overlapping portion 7a is formed to have a size that can be accommodated in the rib 17b formed in the trough 5 of the outer overlapping portion 7b.

  FIG.14 (b) is sectional drawing which shows the state which closed the corrugated pipe | tube 1b from the state of Fig.14 (a). As described above, when the corrugated tube 1b is closed, the outer overlapping portion 7b is overlapped on the outer side of the inner overlapping portion 7a. The rib 17a and the rib 17b are arrange | positioned in the site | part corresponding to a circumferential direction mutually, when the corrugated pipe | tube 1b is closed.

  When the outer overlapping portion 7b and the inner overlapping portion 7a are overlapped, the rib 17a of the inner overlapping portion 7a is accommodated in the rib 17b of the outer overlapping portion 7b. Thereby, it is possible to fix the inner overlapping portion 7a and the outer overlapping portion 7b.

  The ribs 17a and 17b are desirably formed intermittently at a predetermined interval in the direction of the corrugated tube 1b. For example, as shown in FIG. 13, it is desirable to form ribs 17 a and 17 b by skipping one valley portion 5.

  When the ribs 17a and 17b are continuously formed in the tube axis direction, the rigidity of the corrugated tube 1b is increased by the ribs 17a and 17b. For this reason, the bending workability of the corrugated pipe 1b is deteriorated. On the other hand, by forming the ribs 17a and 17b intermittently in the tube axis direction, the corrugated tube 1b can be easily bent at a portion where the ribs 17a and 17b are not formed.

  The ribs 17a and 17b are not limited to being formed in the tube axis direction. For example, like the corrugated pipe 1c shown in FIG. 15, two ribs 17a and 17b may be formed in the pipe axis direction. In this case, the circumferential pitch of the two ribs 17a coincides with the circumferential pitch of the two ribs 17b. For this reason, when the outer overlapping portion 7b and the inner overlapping portion 7a are overlapped, the two ribs 17a of the inner overlapping portion 7a are respectively stored in the two ribs 17b of the outer overlapping portion 7b. Thereby, the inner overlapping portion 7a and the outer overlapping portion 7b can be more reliably fixed.

  As described above, even if a plurality of ribs 17a and 17b are formed in the same number and the same circumferential pitch, the same effect as described above can be obtained.

  The number of ribs 17a and 17b is not limited to the same number. For example, like the corrugated pipe 1d shown in FIG. 16, one rib 17a may be formed in the pipe axis direction and two ribs 17b may be formed in the pipe axis direction. In this case, when the outer overlapping portion 7b and the inner overlapping portion 7a are overlapped, either one of the two ribs 17b of the outer overlapping portion 7b and one rib 17a of the inner overlapping portion 7a are overlapped. Storing. In this way, the inner overlapping portion 7a and the outer overlapping portion 7b can be fixed.

  As described above, even if one rib 17a and a plurality of ribs 17b are formed, the same effect as described above can be obtained. Further, the diameter of the corrugated tube 1d when the tube is closed can be selected by fitting one rib 17a and any one of the plurality of ribs 17b.

  According to the third embodiment, the same effect as that of the first embodiment can be obtained. Further, by forming ribs 17a and 17b that can be fitted to each other on the inner overlapping portion 7a and the outer overlapping portion 7b, the inner overlapping portion 7a and the outer overlapping portion 7b can be more reliably fixed. it can.

(Fourth embodiment)
Next, a fourth embodiment will be described. FIG. 17A is a plan view of the corrugated pipe 1 in an open state. In the present embodiment, the corrugated pipe 1 will be described as an example, but the other corrugated pipes 1a to 1d can be similarly applied. In this embodiment, when the corrugated pipe 1 is closed, the corrugated pipe 1 is twisted and deformed in the circumferential direction.

  In each of the above-described embodiments, when the corrugated pipes are closed, the inner overlapping portions 7a and the outer overlapping portions 7b are fitted with the mountain portions 3 and the valley portions 5 facing each other in the circumferential direction. Combined.

  On the other hand, in this embodiment, the crest portions 3 and the trough portions 5 that face each other in the circumferential direction of the inner overlapping portion 7a and the outer overlapping portion 7b are not overlapped. The crest 3 and the trough 5 of the inner overlapping portion 7a are overlapped and fitted with the crest 3 and the trough 5 of the outer overlapping portion 7b with a predetermined pitch shift in the longitudinal direction of the corrugated tube 1. .

  For example, the peak 3 (for example, W in the figure) of the outer overlapping part 7 b is the peak 3 of the inner overlapping part 7 a and is shifted in the tube axis direction of the corrugated pipe 1 (for example, X in the figure). ). That is, the crests 3 and troughs 5 of all the outer overlapping parts 7b overlap with the crests 3 and troughs 5 of the inner overlapping part 7a that are displaced in the tube axis direction of the corrugated pipe 1 (arrow Y in the figure) ).

  FIG. 17B is a diagram showing a state in which the corrugated tube 1 is closed from the state of FIG. When the crest 3 and the trough 5 of the inner overlapping portion 7a are overlapped with the crest 3 and the trough 5 of the outer overlapping portion 7b by shifting by a predetermined pitch in the longitudinal direction of the corrugated tube 1, they overlap. The mating portion (the end portion of the outer overlapping portion 7b) is formed by being twisted with respect to the tube axis direction.

  In the illustrated example, the crest 3 and trough 5 of the outer overlapping portion 7b are shifted by 1 pitch in the tube axis direction of the corrugated tube 1 and overlapped with the crest 3 and trough 5 of the inner overlapping portion 7a. Although a combined example is shown, the present embodiment is not limited to this. For example, the peak portion 3 and the valley portion 5 of the outer overlapping portion 7 b may be shifted by 2 pitches in the tube axis direction of the corrugated tube 1. When the two pitches are shifted and fitted, the ribs 17a and 17b can be fitted to each other even if the ribs 17a and 17b are formed one pitch at a time as in the corrugated tubes 1b to 1d.

  Here, when the corrugated tube 1 is closed and bent in a predetermined direction, a force may be applied in a direction in which the overlapping portions of the inner overlapping portion 7a and the outer overlapping portion 7b open. However, when the corrugated tube 1 is installed, it is difficult to adjust the position of the overlapping portion in accordance with the bending direction of the corrugated tube 1. Therefore, when the corrugated pipe 1 is bent depending on the bending position and the direction of the overlapping portion, the overlapping portion may be opened by chance.

  On the other hand, in the present embodiment, the circumferential position of the overlapping portion changes with respect to the longitudinal direction of the corrugated tube 1 by twisting and closing the corrugated tube 1. FIG. 18 is a conceptual diagram showing a state where the corrugated pipe 1 is bent. As shown in the figure, the corrugated tube 1 does not become a fixed position even in the bent portion, because the position of the overlapping portion changes in the circumferential direction.

  Thus, since the overlapping part of the corrugated pipe 1 changes in the circumferential direction depending on the part in the longitudinal direction, the overlapping part is disposed over the entire part with a large bending strain when the corrugated pipe 1 is bent. Can be avoided. For this reason, the corrugated pipe 1 is difficult to open. In addition, when a twisting force is applied to the corrugated tube 1 in this way, a shearing force can be applied in a direction that prevents opening of the mouth.

  According to the fourth embodiment, the same effect as that of the first embodiment can be obtained. Further, the position of the overlapping portion (the end portion of the outer overlapping portion 7 and the opening) of the inner overlapping portion 7a and the outer overlapping portion 7b may be formed at an angle with respect to the tube axis direction. it can. For this reason, the opening of the corrugated pipe 1 can be prevented when the corrugated pipe 1 is bent.

  It is also possible to change the diameter of the corrugated tube 1 by changing the twisting pitch of the corrugated tube 1. For example, when the twist amount of the corrugated tube 1 is increased with respect to the corrugated tube 1 that does not form twist, the diameter of the corrugated tube 1 can be decreased.

(Corrugated tube manufacturing method)
Next, a method for manufacturing the corrugated pipe 1 will be described. In the present embodiment, the corrugated pipe 1 will be described as an example, but the other corrugated pipes 1a to 1d can be manufactured in the same procedure.

  FIG. 19A is a diagram showing the corrugated element tube 20. The corrugated element tube 20 is manufactured, for example, by extrusion. For example, a resin is extruded into a cylindrical shape from an extruder to form a cylindrical material. Further, the mold is repeatedly transported and fed while synchronizing the transport speed of the mold installed on the endless track with the extrusion speed of the cylindrical material.

  The cylindrical material is formed by being sandwiched between a pair of molds. The mold is a half-cylinder half-cylinder member in which irregularities and the like corresponding to the outer shape of the corrugated base tube 20 are formed on the inner surface. The pair of molds face each other to form a cylindrical member, and a crest and a trough corresponding to the outer shape of the corrugated base tube 20 are formed on the inner surface.

  The corrugated element tube 20 is a generally tubular member that does not have an opening along the longitudinal direction. In the corrugated element tube 20, a plurality of crest portions 3 and trough portions 5 extending in the circumferential direction are alternately formed at predetermined intervals in the tube axis direction.

  In the cross-section perpendicular to the longitudinal direction of the corrugated element tube, the corrugated element tube 20 is overlapped with a part of the corrugated element tube 20 in the circumferential direction so that the peak portions 3 and the valley portions 5 of the corrugated element tube 20 overlap each other. Part 7. One end portion side of the overlapping portion 7 is an inner overlapping portion 7a, and the other end portion side is an outer overlapping portion 7b.

  A connecting portion 21 where the inner overlapping portion 7a and the outer overlapping portion 7b are connected is formed between the opposing portions of the inner overlapping portion 7a and the outer overlapping portion 7b of the corrugated tube 1. Further, a curved connection portion 9 is formed between the other of the inner overlapping portion 7a and the outer overlapping portion 7b of the corrugated tube 1. That is, the curve connecting portion 9 is a portion that connects the inner overlapping portion 7a and the outer overlapping portion 7b.

  In the corrugated element tube 20, the inner overlapping portion 7 a is arranged on the outer peripheral side from the outer overlapping portion 7 b. That is, in the vicinity of the connecting portion 21, the distance from the center position of the curved connecting portion 9 to the outer surface of the inner overlapping portion 7a is longer than the distance from the central position of the curved connecting portion 9 to the inner surface of the outer overlapping portion 7b.

  Further, when comparing the curvature radius of the inner peripheral surface of the inner overlapping portion 7a and the curvature radius of the outer overlapping portion 7b, the curvature radius of the inner overlapping portion 7a is larger than the curvature radius of the outer overlapping portion 7b. Further, the center of the radius of curvature of the outer overlapping portion 7b is disposed at a position offset from the center position of the curve connecting portion 9 toward the outer overlapping portion 7b.

  In addition, here, the structure in which the center of the radius of curvature of the outer overlapping portion 7b is arranged at a position offset from the center of the curve connecting portion 9 toward the outer overlapping portion 7b is shown. It is also possible to arrange the center of the radius of curvature at a position offset from the center position of the curve connection portion 9 to the curve connection portion 9 side in the direction opposite to the inner overlapping portion 7a side. That is, it is only necessary that the center of the radius of curvature of at least one of the inner overlapping portion 7a and the outer overlapping portion 7b is offset from the center of the curve connecting portion 9.

  The distance from the outer peripheral surface at the tip of the inner overlapping portion 7a to the center position of the curve connecting portion 9 is 2 to 2 from the distance from the inner peripheral surface at the tip of the outer overlapping portion 7b to the center position of the curved connecting portion 9. 10% larger is desirable.

  A step 13a is provided in the circumferential direction at the boundary between the inner overlapping portion 7a and the curved connection portion 9. Due to the stepped portion 13 a, the outer peripheral surface of the peak portion 3 of the inner overlapping portion 7 a is positioned inside the outer peripheral surface of the peak portion 3 of the curved connection portion 9. Similarly, a stepped portion 13b is provided in the circumferential direction at the boundary between the outer overlapping portion 7b and the curve connecting portion 9. Due to the stepped portion 13 b, the inner peripheral surface of the valley portion 5 of the outer overlapping portion 7 b is positioned outside the inner peripheral surface of the valley portion 5 of the curved connection portion 9.

  The corrugated pipe 1 having the opening 11 can be manufactured by cutting the connecting portion 21 of the corrugated base pipe 20 with the blade 23. That is, the corrugated pipe 1 can be manufactured using the corrugated base pipe 20. As described above, the corrugated tube 1 manufactured in this way has the curved connecting portion 9 reduced in diameter, and the crest portions 3 and the trough portions 5 of the inner overlap portion 7a and the outer overlap portion 7b. Can be superimposed. Therefore, the corrugated tube 1 can be closed.

  When the corrugated tube 1 is closed by reducing the diameter of the curved connection portion 9, the inner overlap is performed so as to contact a part or the whole of the inner peripheral surface of the peak portion 3 and the valley portion 5 of the outer overlap portion 7b. The mating portion 7a is superimposed on the inner side of the outer overlapping portion 7b. At this time, the outer peripheral surfaces of the crest 3 and trough 5 of the inner overlapping portion 7a exert an elastic repulsive force on the crest 3 and trough 5 of the outer overlapping portion 7b.

  As described above, in order to maintain the closed tube state, heat treatment may be performed at the time of closing the tube or after the tube is closed. By doing in this way, the corrugated pipe | tube 1 can be stably maintained with the closed tube shape.

  As described above, the corrugated tube 1 can be easily manufactured by using the corrugated tube 20.

  As mentioned above, although embodiment of this invention was described referring an accompanying drawing, the technical scope of this invention is not influenced by embodiment mentioned above. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs.

  For example, it goes without saying that the above-described configurations can be combined with each other.

1, 1a, 1b, 1c, 1d ......... corrugated tube 3 ......... mountain 5 ......... valley 7 ...... overlapping portion 7a ......... inner overlapping portion 7b ......... outer overlapping portion 9 ......... Curve connecting part 11 ......... Opening parts 13a and 13b ......... Step parts 15a and 15b ......... Walls 17a and 17b ......... Rib 20 ......... Corrugated tube 21 ......... Connecting part 23 …… ... cutlery

Claims (21)

A corrugated pipe in which crests and troughs extending in the circumferential direction are repeatedly formed in the pipe axis direction alternately at a predetermined interval,
In the cross section perpendicular to the longitudinal direction of the corrugated pipe, the crests and the troughs of the corrugated pipe overlap each other at both ends in the circumferential direction of the corrugated pipe. An overlapping portion and a curved connecting portion connecting the overlapping portions at both ends;
It is possible to close the tube by overlapping the crests and the troughs of the overlapping part,
In a state where the corrugated tube is opened without overlapping the overlapping portion, in the cross section perpendicular to the longitudinal direction of the corrugated tube, one overlapping portion is an inner overlapping portion, and the other overlapping portion is An outer overlapping portion, and the inner overlapping portion is arranged on the outer peripheral side from the outer overlapping portion,
When the curved connecting portion is reduced in diameter and closed, the outer peripheral surfaces of the crest and trough of the inner overlap portion are elastic repulsive force with respect to the crest and trough of the outer overlap portion. And the inner overlapping portion can be overlapped inside the outer overlapping portion so as to be in contact with a part or all of the inner peripheral surface of the crest portion and the trough portion of the outer overlapping portion. Corrugated tube characterized by being.   In a state perpendicular to the longitudinal direction of the corrugated tube in a state where both ends in the circumferential direction of the corrugated tube are butted, the radius of curvature of the inner peripheral surface of the inner overlapping portion and the radius of curvature of the outer overlapping portion are In comparison, the radius of curvature of the inner overlapping portion is larger than the radius of curvature of the outer overlapping portion, and at least one of the centers of the curvature radii of the inner overlapping portion and the outer overlapping portion is the curve connecting portion. The corrugated pipe according to claim 1, wherein the corrugated pipe is disposed at a position offset from a center position.   The center of the radius of curvature of the inner overlapping portion is disposed at a position offset from the center of the curve connecting portion toward the curve connecting portion in the direction opposite to the inner overlapping portion, or the curvature of the outer overlapping portion. The corrugated pipe according to claim 2, wherein the center of the radius is at least one of a position offset from a center position of the curved connection portion toward the outer overlapping portion.   In a state where both ends in the circumferential direction of the corrugated pipe are butted, the distance from the outer peripheral surface of the tip of the inner overlapping portion to the center position of the curved connecting portion is from the inner peripheral surface of the tip of the outer overlapping portion. 4. The corrugated pipe according to claim 3, wherein the corrugated pipe is 2 to 10% larger than a distance to a center position of the curved connection portion.   The boundary portion between the inner overlapping portion and the curved connection portion and the boundary portion between the outer overlapping portion and the curved connection portion have step portions with respect to the circumferential direction, respectively, and each of the boundary portions The outer peripheral surface of the peak portion of the inner overlapping portion is positioned inside the outer peripheral surface of the peak portion of the curved connection portion, and the inner peripheral surface of the valley portion of the outer overlapping portion is the curved connection. The corrugated pipe according to any one of claims 1 to 4, wherein the corrugated pipe is formed on an outer side than an inner peripheral surface of the valley portion of the portion.   The corrugated pipe according to any one of claims 1 to 5, wherein a thickness of the inner overlapping portion and the outer overlapping portion is formed thinner than a thickness of the curved connection portion.   The step portion formed at the boundary portion between the inner overlapping portion and the curved connection portion includes a side wall of the peak portion sandwiching the valley portion from both sides on the outer peripheral surface of the valley portion of the inner overlapping portion. A wall is formed so as to connect to the stepped portion formed at the boundary portion between the outer overlap portion and the curved connection portion, on the inner peripheral surface of the mountain portion of the outer overlap portion. 6. The corrugated pipe according to claim 5, wherein a wall is formed so as to connect the side walls of the valley part sandwiching the mountain part from both sides.   The thickness of the central portion in the circumferential direction of the curved connection portion is formed thinner than the thickness of both side portions sandwiching the central portion in the circumferential direction of the curved connection portion, or the thickness of the central portion in the circumferential direction of the curved connection portion The wall thickness is formed so that the wall thickness gradually decreases from both sides of the central portion in the circumferential direction of the curved connection portion toward the central portion of the curved connection portion. A corrugated tube according to any one of the above.   The angle at which the inner overlap portion is formed in the circumferential direction with respect to the center of the curved connection portion is in the range of 35 ° to 65 °, and the angle at which the outer overlap portion is formed is from 35 ° to 35 °. It is a range of 65 degree | times, Furthermore, the formation length of the circumferential direction of the said inner side overlapping part is more than the formation length of the said outer side overlapping part, The Claim 1 characterized by the above-mentioned. Corrugated tube as described.   When the inner overlapping portion and the outer overlapping portion are overlapped, the length of the inner overlapping portion that is not overlapped and is exposed is 1/3 of the circumferential length of the inner overlapping portion. The corrugated pipe according to any one of claims 1 to 9, wherein the corrugated pipe is in the following range. As the width of the inner peripheral surface of the crest portion of the outer overlapping portion gradually increases toward the base portion of the crest portion, the outer periphery of the crest portion of the inner overlapping portion that is further widened and fitted therein The width of the surface is formed narrower than the width of the inner peripheral surface of the mountain portion of the outer overlapping portion,
When the outer overlapping portion and the inner overlapping portion are overlapped, the width direction of the inner peripheral surface of the peak portion of the outer overlapping portion and the outer peripheral surface of the peak portion of the inner overlapping portion is increased. It has a clearance of the range of 10-20% of one side with respect to the width | variety of the internal peripheral surface of the said peak part of the said outside overlap part in the middle. Corrugated tube. The height of the outer peripheral surface of the peak portion of the inner overlapping portion is lower than the height of the inner peripheral surface of the peak portion of the outer overlapping portion,
When the outer overlapping portion and the inner overlapping portion are overlapped, the height direction of the inner peripheral surface of the peak portion of the outer overlapping portion and the outer peripheral surface of the peak portion of the inner overlapping portion 12. The clearance according to claim 1, further comprising a clearance in a range of 10 to 20% with respect to a height of an inner peripheral surface of the peak portion of the outer overlapping portion. Corrugated tube as described.   The thickness of the top portion of each of the peak portions of the inner overlapping portion and the outer overlapping portion is smaller than the thickness of the curved connection portion, and the total thickness of the inner overlapping portion and the outer overlapping portion. The corrugated pipe according to any one of claims 1 to 12, wherein a value is larger than a thickness of the curved connection portion.   The corrugated pipe is torsionally deformed in a circumferential direction, and the crest and trough of the inner overlapping section are longer than the crest and trough of the outer overlapping section. The corrugated pipe according to any one of claims 1 to 13, wherein the corrugated pipe is formed by being overlapped with a predetermined pitch and fitted, and the overlapped portion is twisted with respect to a pipe axis direction. .   The corrugated pipe according to claim 14, wherein the corrugated pipe is bent. The overlap portion is formed with a rib that connects the peak portions in the tube axis direction along the tube axis direction, and the rib formed in the valley portion of the inner overlap portion is the outer overlap portion. Formed in a dimension that can be accommodated in the rib formed in the valley of
When the inner overlapping portion and the outer overlapping portion are overlapped, the rib of the inner overlapping portion is accommodated in the rib of the outer overlapping portion, and the overlapping portion is fixed. The corrugated pipe according to any one of claims 1 to 15, wherein the corrugated pipe is possible.   The corrugated pipe according to claim 16, wherein the ribs are formed intermittently at predetermined intervals in the axial direction of the corrugated pipe. A corrugated element tube in which crests and troughs extending in the circumferential direction are repeatedly formed in the tube axis direction alternately at a predetermined interval,
In a cross section perpendicular to the longitudinal direction of the corrugated element tube, the ridges and valleys of the corrugated element tube overlap each other in a part of the circumferential direction of the corrugated element tube, A curve connecting portion that connects the overlapping portions, and a connecting portion that connects the overlapping portions,
In a cross section perpendicular to the longitudinal direction of the corrugated tube, one of the overlapping portions is an inner overlapping portion, the other overlapping portion is an outer overlapping portion, and the inner overlapping portion is the outer overlapping portion. It is arranged on the outer peripheral side from the overlapping part,
Comparing the curvature radius of the inner peripheral surface of the inner overlapping portion and the curvature radius of the outer overlapping portion, the curvature radius of the inner overlapping portion is larger than the curvature radius of the outer overlapping portion, and the inner overlapping portion is larger. The center of the radius of curvature of the portion is disposed at a position offset from the center of the curved connecting portion toward the curved connecting portion in the direction opposite to the inner overlapping portion, or the radius of curvature of the outer overlapping portion is The corrugated element tube is characterized in that the center is at least one of a position offset from a center position of the curved connection portion to the outer overlapping portion side.   The distance from the outer peripheral surface at the tip of the inner overlapping portion to the center position of the curved connection portion is 2 to 10% from the distance from the inner peripheral surface of the tip of the outer overlapping portion to the central position of the curved connection portion. 19. The corrugated element tube according to claim 18, wherein the corrugated element tube is large. A method for producing a corrugated pipe using the corrugated pipe according to claim 18 or 19,
A corrugated tube having an opening by cutting the connecting portion of the corrugated tube,
The corrugated tube can be closed by reducing the diameter of the curved connecting portion and closing the inner overlapping portion on the inner side of the outer overlapping portion.   When the curved connecting portion is reduced in diameter and closed, the outer peripheral surfaces of the crest and trough of the inner overlapping portion are elastically repelled with respect to the crest and trough of the outer overlapping portion. Exerting a force and superimposing the inner overlapping portion on the inner side of the outer overlapping portion so as to contact a part or all of the inner peripheral surface of the crest portion and the trough portion of the outer overlapping portion. 21. A method of manufacturing a corrugated pipe according to claim 20, wherein

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