JP2004312948A - Slit corrugate tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a slip from opening when a corrugate tube is bent. <P>SOLUTION: In a resin slit corrugate tube 10 for externally protecting a wire group by opening a slit 13 made along the axial direction provided alternately with crests 12 and roots 11 and inserting the wire group laterally, the length L1 in the axial direction on the top surface 12a of the crest is differentiated from the length L2 in the axial direction on the bottom face 11a of the root, the L1 is set equal to 2-4 times of the L2, a large R is set between the bottom face 11a and the side face 11b of the root 11, and the height H from the bottom face 11a of the root to the top surface 12a of the crest is set in the range of 1.5-4.0 mm. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a corrugated tube with a slit, and more particularly, to a sheathed wire harness that is routed to an automobile, which prevents an axial slit from opening when a corrugated tube is bent. Is what you do.
[0002]
[Prior art]
Conventionally, wire harnesses routed to automobiles have a corrugated tube made of synthetic resin to prevent the wires of the wire harness from being damaged by interferences such as protrusions and edges at the location of the wire harness. To protect the exterior. As shown in FIG. 4, this type of corrugated tube 1 is formed of a bellows-shaped cylinder in which annular ridges 2 and valleys 3 are provided alternately in the axial direction. Are flexed accordingly.
The corrugated tube 1 is provided with a slit 4 that can be expanded along the entire length in the axial direction so that the corrugated tube 1 can be attached to the wire harness so as to cover the wire harness from the side, and the slit 4 is formed. It has a so-called cracked shape, which is an opening for attachment to the wire harness.
[0003]
In the conventional corrugated tube shown in FIG. 4, the peak height from the bottom surface of the valley to the top surface of the peak is set to about 1.5 to 1.8 mm and less than 2 mm. In addition, the axial length of the peak top surface and the axial length of the valley bottom surface are often substantially equal.
[0004]
In this type of corrugated tube with a slit, as shown in FIG. 5, the slit 4 is greatly opened at the bent portion and the mouth is easily opened, and in that case, the electric wire w of the wire harness W / H inserted therein is easily protruded. There's a problem. If the electric wire w protrudes outside of the corrugated tube 1, there is a problem that the electric wire w is damaged by the above-mentioned interfering substance or the like existing at the wiring site.
[0005]
Various countermeasures have been taken against the above problem, and generally, as shown in FIG. 6, a tape T is wound around the outer surface of the corrugated tube 1 to cope with the opening phenomenon of the slit 4. Often do.
Alternatively, in Japanese Unexamined Patent Application Publication No. 2000-287330, as shown in FIGS. 7A and 7B, the corrugated tube 5 can be disengaged from one end 8 and the other end 9 forming a slit S in the axial direction. The lock claws 8a and 9a are protruded so as to face each other, and by engaging the lock claws 8a and 9a with each other, the slit S is prevented from opening.
[0006]
[Patent Document 1]
JP 2000-287330 A
[Problems to be solved by the invention]
However, in the case where the tape T is wound around the outer peripheral surface of a generally-used corrugated tube to prevent the mouth from opening, there is a problem that the cost is increased, for example, the cost of the tape and the number of labor required for winding the tape are increased.
Further, in the corrugated tube 5 shown in FIGS. 7A and 7B, since the lock claws 8a and 9a protrude from the slit portion S serving as a mounting opening for the wire harness W / H, the wire harness W / H is not provided. There is a problem that the electric wire is hooked on the lock claws 8a and 9a at the time of mounting, and the mounting workability is deteriorated. Further, after the wire harness W / H is inserted into the corrugated tube 5, the work of engaging the opposing lock claws 8a and 9a must be separately performed, and there is a problem that the number of work steps increases. Furthermore, since the corrugated tube provided with the above-mentioned lock structure is formed, there is a problem that the mold becomes complicated and the cost increases.
[0008]
The present invention has been made in view of the above problems, and has as its object to prevent opening of a slit in a corrugated tube when the corrugated tube is bent without deteriorating the mounting workability of the corrugated tube.
[0009]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the present invention provides a method in which peaks and valleys are alternately provided in the axial direction, and one slit is provided along the axial direction. A horizontal corrugated tube with a slit made of resin to insert and insert the wire group to protect the wire group.
The length L1 in the axial direction of the top surface of the crest is different from the length L2 in the axial direction of the bottom surface of the valley, L1 is set to 2 to 4 times L2, and the radius between the bottom surface and the side surface of the valley is reduced. A corrugated tube with a slit is provided which is large and has a peak height H from the bottom of the valley to the top of the peak of 1.5 mm to 4.0 mm.
[0010]
With the above configuration, by making the corrugated tube higher in height than the conventional corrugated tube, the portion that can follow the curvature of the corrugated tube, that is, the length of the side surface of the valley is increased, so that Can sufficiently spread in the axial direction following the curvature of the corrugated tube, and can prevent a slit serving as an insertion portion of the electric wire group from opening. In addition, by increasing the axial length of the crest top surface, the flexibility of the corrugated tube is increased, and the corrugated tube can easily follow the bending, and the side surface of the crest can easily follow the curvature of the corrugated tube.
In addition, the radius between the bottom and the side of the valley is large to make it a gentle arc surface, and when the corrugated tube is curved, it is easy to deform between the bottom and the side of the valley, so the slit Can be more reliably prevented from opening. It is preferable that the radius is 30φ to 150φ.
Further, after the corrugated tube has been sheathed in the wire harness, it is not necessary to wind the corrugated tube with tape or the like, so that the cost of parts can be reduced and the number of working steps can be prevented from increasing.
Furthermore, since the corrugated tube is not provided with a complicated lock structure, the cost of the mold does not increase.
[0011]
The outer diameter of the crest top is 1.28 to 1.50 times the outer diameter of the trough bottom, and the crest height H is 2.8 to 4.5 times the axial length L2 of the trough bottom. In addition, it is preferable that the axial length L1 of the crest top surface is 2.4 to 3.3 times the axial length L2 of the trough bottom surface.
[0012]
The reason why the outer diameter of the crest top surface is 1.14 to 1.25 times the outer diameter of the valley bottom surface and the crest height H is 2.8 to 4.5 times the axial length of the valley bottom surface L2 is as follows. If the height is smaller than the above range, the peak height is low and the side surface of the valley portion is short, so that when the corrugated tube is curved, the side surface does not sufficiently expand following the curvature of the corrugated tube. On the other hand, if it is larger than the above range, when the corrugated tube is curved, the ridges inside the bent position easily interfere with each other. If the corrugated tube is further bent in this state, the side surface of the valley does not expand in the axial direction of the corrugated tube, but expands in the direction perpendicular to the axis, and the slit opens. Also, the outer shape of the corrugated tube becomes too large.
The reason why the axial length L1 of the peak top surface is set to 2.4 to 3.3 times the axial length L2 of the valley bottom surface is that if the length is smaller than 2.4 times, the flexibility of the corrugated tube decreases. It is. On the other hand, if it is greater than 3.3 times, the axial length of the bottom of the valley becomes small, and when the corrugated tube is curved, the ridges inside the bent position easily interfere with each other. If the corrugated tube is further bent in this state, the slit opens.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIGS. 1 to 3 show a corrugated tube 10 with a slit (hereinafter, “corrugated tube 10”) according to an embodiment of the present invention. The corrugated tube 10 is made of polypropylene or nylon, has a bellows-like cylindrical shape in which annular valleys 11 and ridges 12 are alternately provided at the same pitch in the axial direction, and extends along the entire length in the axial direction. The slit 13 is formed in a notched cracked shape.
The corrugated tube 10 is attached to a wire harness arranged in an automobile from the side in a direction perpendicular to the axis, with the slit 13 as an opening.
[0014]
The valley portion 11 includes a bottom surface 11a and side surfaces 11b on both sides of the bottom surface 11a, and a connecting portion 11c between the bottom surface 11a and the side surface 11b is a circular arc having a radius of 30φ.
[0015]
As shown in FIG. 2, the corrugated tube 10 is configured such that the axial length L1 of the top surface 12a of the peak portion 12 is 2.0 mm, and the axial length L2 of the bottom surface 11a of the valley portion 11 is 0.7 mm. Is about 2.9 times L2. In addition, the peak height H from the valley bottom surface 11a to the peak top surface 12a is set to 2.63 mm. The outer diameter L3 of the crest top surface 12a is 19.9 mm, the outer diameter L4 of the valley bottom surface 11a is 14.7 mm, and L3 is 1.35 times L4 and H is 2.9 times L2. The axial length L5 of the side surface 11b of the valley 11 is 0.4 mm, and the pitch L6 between the valley 11 and the ridge 12 is 3.5 mm.
[0016]
As shown in FIG. 3, when the corrugated tube 10 is curved, a tensile force in the axial direction is applied to the outside 10 a of the corrugated tube 10 at the bending position. At this time, the side surface 11b of the valley portion 11 of the corrugated tube 10 expands in the axial direction following the tensile force.
[0017]
With the above configuration, in the corrugated tube 10, the axial length of the expandable side surface 11b is increased by increasing the peak portion 12, and the bottom surface 11a and the side surface 11b of the valley portion 11 are formed into gentle arc surfaces. Thus, when the corrugated tube 10 is curved, the side surface 11b is easily spread. Accordingly, when the corrugated tube 10 is curved, the side surface 11b of the outer side 10a expands sufficiently following the tensile force generated by the curvature, so that the slit 13 serving as the insertion portion of the electric wire group is prevented from opening. Can be.
[0018]
Further, after the corrugated tube 10 is covered with the wire harness, no special work is required. For example, since it is not necessary to wind the tape with tape, it is possible to reduce the cost of parts and to prevent an increase in the number of work steps. Can be. Further, since the corrugated tube 10 is not provided with a complicated lock structure, the cost of the mold does not increase.
[0019]
【The invention's effect】
As is clear from the above description, according to the present invention, by making the height of the peak of the corrugated tube higher than that of the conventional corrugated tube, the corrugated tube can be expanded by the tensile force in the axial direction of the corrugated tube. Since the side surface is elongated and sufficiently widened in the axial direction following the tensile force generated when the side surface curves the corrugated tube, it is possible to prevent the slit serving as the insertion portion of the electric wire group from opening.
[0020]
Further, if the bottom surface of the valley portion and the side walls are formed as gentle arc surfaces, when the corrugated tube is curved, the side surface is easily expanded, so that the opening of the slit can be more reliably prevented.
Further, after the corrugated tube has been sheathed in the wire harness, it is not necessary to wind the corrugated tube with tape or the like, so that the cost of parts can be reduced and the number of working steps can be prevented from increasing.
Furthermore, since the corrugated tube is not provided with a complicated lock structure, the cost of the mold does not increase.
[Brief description of the drawings]
FIG. 1A is a side view of a corrugated tube of an embodiment, and FIG. 1B is a cross-sectional view taken along line I1-I1.
FIGS. 2A and 2B are enlarged views of a main part of a corrugated tube. FIG. 3 is a drawing showing a state in which the corrugated tube is curved.
FIG. 4A is a side view of a conventional corrugated tube, and FIG. 4B is a sectional view taken along line I2-I2.
FIG. 5 is a view showing a conventional problem.
FIG. 6 is a drawing showing a conventional corrugated tube wound with a tape.
FIG. 7A is a perspective view showing another conventional example, and FIG. 7B is a front view.
[Explanation of symbols]
10 Corrugated tube 11 Valley 11a Bottom 11b Side 12 Mountain 12a Top 13 Slit

Claims (2)

Crests and valleys are alternately provided in the axial direction, and one slit is provided along the axial direction. The slit is opened, and a group of electric wires is inserted and inserted into the inside thereof. A corrugated tube with a slit made of resin to protect the exterior,
The length L1 in the axial direction of the top surface of the crest is different from the length L2 in the axial direction of the bottom surface of the valley, L1 is set to 2 to 4 times L2, and the radius between the bottom surface and the side surface of the valley is reduced. A corrugated tube with slits, wherein the corrugated tube has a large height and a peak height H from the bottom of the valley to the top of the peak is set to 1.5 mm to 4.0 mm. The outer diameter of the crest top is 1.28 to 1.50 times the outer diameter of the trough bottom, and the crest height H is 2.8 to 4.5 times the axial length L2 of the trough bottom. 2. The corrugated tube with slits according to claim 1, wherein an axial length L1 of the crest top surface is 2.4 to 3.3 times an axial length L2 of the valley bottom surface. 3.

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