JPH11187549A - Wire protective tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wire protective tube which enables reduction of an air resistance and an air noise. SOLUTION: A protective tube 10 consists of a long cylindrical main part 11 which has a dividing line 17 in its lower part in a longitudinal direction and a pair of flange parts 13a and 13b which are pressed against each other and extended vertically downward from both the edges of the dividing line 17. A number of real circular dimples 15 are formed on the outer circumference of the protective tube 10. The diameters and depths of the dimples 15 are approximately 2-5 mm and 0.05-0.5 mm respectively. The respective dimples 15 are densely arranged hexagonally. The protective tube 10 is integrally molded by using a mold in which protrusions corresponding to the dimples 15 are formed beforehand.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric wire protection tube provided to cover an outer periphery of an electric wire and protecting the electric wire.

[0002]

2. Description of the Related Art Conventionally, when performing construction work using a large machine such as a crane near an electric wire, it is necessary to prevent the machinery from directly touching the electric wire during the work and cutting the electric wire. For this purpose, the outer periphery of a predetermined portion of the electric wire near the work site is covered with an electric wire protection tube (hereinafter, simply referred to as a “protection tube”) formed of an insulating material such as polyethylene.

As shown schematically in FIG. 8, a conventional protective tube 100 has a crevice 107 in a longitudinal direction of a lower portion of a cylindrical main body.
And a pair of flange portions 103 that abut against each other from both ends of the split 107 and extend in the outer peripheral direction.
a and 103b. The protection tube 100
The electric wire is formed of a flexible resin member, and the electric wire is inserted into the pipe main body 101 by the flange portions 103a and 103b contacting each other being opened in a direction away from each other.

[0004]

However, since the conventional protective tube 100 has a large surface area as compared with the electric wire and receives a large wind pressure in a strong wind or the like, it causes the electric wire inserted inside to sway. Becomes Therefore, the protective tube 1
00 applies a load to the electric wire in the shearing direction, and in some cases, there is a problem that the electric wire may be broken.

Further, in consideration of such a problem, the strength of the electric wire itself must be set to a certain high level, and there is a problem that the cost is high. Furthermore, the protective pipe 10
0, the transverse (perpendicular to the longitudinal direction) component of the airflow flowing on its flat outer surface is
In the first half of 00, it flows along the surface of the protective tube and forms a laminar boundary layer. And it peels largely at the position which entered into the latter half surface of the protection pipe 100 a little. This separation has a problem that a so-called Karman vortex is regularly generated, and a pressure fluctuation caused by the generation of the vortex generates aerodynamic noise, thereby injuring surrounding residents.

Accordingly, an object of the present invention is to provide an electric wire protection tube capable of reducing air resistance and air noise.

[0007]

Means for Solving the Problems and Effects of the Invention In view of the above-mentioned problems, a protective tube according to the present invention comprises: a main body having a cylindrical long axis shape having a lower longitudinally cleaved end; And a pair of flanges extending vertically downward from the pair of flanges, a wire is drawn in between the pair of flanges, and the protective tube holds the wires in the main body. A plurality of concave portions are provided.

[0008] According to the above configuration, when the air flow flows on the outer surface of the protection tube, the air flow separates slightly at a location approaching the concave portion, and the separated air flows interfere with each other. Then, due to the turbulence of the airflow on this surface, the boundary layer that had been a laminar boundary layer when the outer surface was flat is likely to change to a turbulent boundary layer. When the surface becomes a turbulent boundary layer, the airflow on the protective tube surface becomes less likely to separate than the laminar boundary layer, and the separation becomes irregular, so that regular occurrence of Karman vortices is eliminated and aerodynamic noise is reduced .

[0009] The concave portion may be specifically formed in a dimple shape. In this case, it is preferable to arrange the dimples in a hexagonal close-packed state. It is well known that a large number of dimples are provided around the golf ball, for example, in order to increase the flight distance of the golf ball. This is to reduce air resistance by effectively generating turbulence around the golf ball.

The above configuration is an application of this.
That is, by performing dimple processing on the outer surface of the protective tube as described above, when a strong wind sweeps the outer surface of the protective tube, the boundary layer on the surface is easily changed from a laminar boundary layer to a turbulent boundary layer. . In other words, many small separations occur in the airflow flowing along the surface of the protective tube, and the turbulence of the airflow on the surface of the protective tube due to the small separation causes the boundary layer on the surface to be turbulent from the laminar boundary layer. Change to boundary layer. When the surface becomes a turbulent boundary layer, the airflow on the surface of the protective tube becomes less likely to separate than the laminar boundary layer, and the separation becomes irregular, so that the regular occurrence of Karman vortices disappears and the air resistance decreases. At the same time, aerodynamic noise is reduced.

The recess is formed by a groove formed in the main body in a circumferential direction perpendicular to the longitudinal direction, and a groove formed in the flange portion in a direction extending from the main body. It may also be characterized by that. According to the above configuration, in the airflow flowing along the protective tube, the airflow sweeping the outer periphery and the airflow flowing through the groove interfere with each other at the separation position to form a turbulent boundary layer. As a result, the occurrence of Karman vortices is suppressed, the air resistance is reduced, and the aerodynamic noise is reduced.

Further, the recess may be formed by a groove formed in parallel with the longitudinal direction of the main body and the flange portion. According to the above configuration, the air flow flowing along the protection tube causes small separation near the boundary between the groove and the outer surface of the protection tube, and forms a turbulent boundary layer on the surface of the protection tube. The generation of the vortex is suppressed, the air resistance is reduced, and the aerodynamic noise is reduced.

Further, the recess may be formed by a spiral groove. That is, the above configuration has a shape in which the groove provided in parallel with the longitudinal direction is twisted along the outer periphery of the protection tube. By adopting such a configuration, the position of the separation point of the airflow on the surface of the protection tube is shifted on the circumference, so that the effect of mutual interference of the separated airflows can be further enhanced.

Further, the protective tube of the present invention comprises a main body having a cylindrical long axis shape and having a split in a lower longitudinal direction, and a pair of flange portions extending vertically downward from both end edges of the split. A plurality of protrusions are provided on the outer surfaces of the main body and the flange portion in the electric wire protection tube for drawing an electric wire from between the pair of flange portions and holding the electric wire in the main body.

That is, contrary to the configuration described above, by providing a plurality of convex portions on the outer periphery of the protective tube, the flow of the airflow flowing around the outer periphery is locally deflected, and Interfere with each other to form a turbulent boundary layer.

Specifically, the convex portion may be constituted by a pair of small pieces formed by standing two thin plate-like small pieces. In this case, it is preferable that the small piece pair is configured such that the two small pieces are erected in a C shape. With the above configuration, the air flow flowing along the protective tube is compressed or diffused when passing between the two small pieces of the small piece pair. Then, this air flow interferes with the air flow passing between adjacent small-piece pairs or between two small-pieces constituting the adjacent small-piece pair to form a turbulent boundary layer. As a result, generation of Karman vortex is suppressed, and both air resistance and air noise are reduced.

Further, the convex portion may be constituted by a conical small projection. With the above configuration, when the airflow flows on the outer surface of the protective tube, many small separations occur in the airflow flowing along the surface of the protection tube, and due to the turbulence of the airflow on the surface of the protection tube due to the small separation. The boundary layer changes from a laminar boundary layer to a turbulent boundary layer. For this reason, regular occurrence of Karman vortices is eliminated, and air resistance and aerodynamic noise are reduced.

Further, the projection may be constituted by a mesh-like projection formed in a mesh. With the above configuration, the airflow flowing along the surface of the protective tube makes small separation locally via the mesh-like projections. The turbulent boundary layer is formed by the turbulence of the airflow on the surface of the protective tube due to the small separation, and the regular generation of Karman vortices is eliminated, and the air resistance and aerodynamic noise are reduced.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings in order to further clarify the embodiments of the present invention. [First Embodiment] FIG. 1 is a perspective view of a protective tube according to a first embodiment of the present invention.

The protective tube 10 comprises a main body 11 having a cylindrical longitudinal axis and having a lower portion 17 in the longitudinal direction, and a pair of flange portions 1 abutting each other from both end edges of the split and extending vertically downward.
3a and 13b. The flange part 1
3a and 13b are integrally formed with the main body 11.
The dimensions of each part of the protective tube 10 are as follows: the total length of the main body 11 is 2 to 3 m, the outer diameter is 30 to 60 mm, and the inner diameter is 2 mm.
The flange portions 13a, 13
b has a length of 10 to 30 mm in the protruding direction from the main body 11. Further, since the protective tube 10 is formed of an insulating resin such as polyethylene having flexibility, the flange portions 13a and 13b which are in contact with each other can be easily opened in a direction away from each other, At this time, the electric wire can be inserted into the main body 11 from the opened opening.

On the outer periphery of the protective tube 10, a large number of dimples 15 having a perfect circular shape are formed. This dimple 1
5 is 2-5 mm in diameter and 0.05-0.5 mm in depth
, Each of which is densely arranged in hexagons. The protective tube 10 is integrally formed by using a mold in which a convex portion corresponding to the dimple shape is formed in advance.

By forming the outer surface of the protective tube 10 into a dimple shape as described above, the boundary layer formed by the airflow flowing on the outer surface of the protective tube 10 in a strong wind is changed from the laminar boundary layer to the turbulent boundary layer. It becomes easy to change. That is, the air flow flowing along the outer surface of the protective tube 10 is separated at the above-mentioned many dimples to a small extent. It changes from a layer to a turbulent boundary layer. When the surface becomes the turbulent boundary layer, the airflow on the surface of the protective tube 10 is less likely to separate than the laminar boundary layer, or promotes reattachment of the separation, so that the regular occurrence of Karman vortices is eliminated and the air resistance is reduced. And aerodynamic noise is reduced.

In the present embodiment, the dimple 15 is a perfect circle, but is not limited to this, and may be an ellipse, a slightly distorted circle, or a polygon such as a hexagon. Further, the cross-sectional shape of the dimple 15 is not limited to the above shape, but may be various shapes such as a square shape. Further, although the dimples 15 are arranged in a hexagonal close-packed state, they may be arranged at random or may be arranged at predetermined intervals.

Further, the size of the dimple 15 is not limited to the above-described size, but may be appropriately selected according to the level of generated air noise or the like. [Second Embodiment] FIG. 2 is a perspective view of a protective tube 20 according to a second embodiment of the present invention.

The structure of the protection tube 20 is the same as that of the first embodiment except for the shape of the concave portion formed on the outer surface, and the description of the same components will be omitted. In the protective tube 20, a plurality of grooves 25 are formed on the outer surfaces of the main body 21 and the flange portions 23a and 23b in a direction perpendicular to the longitudinal direction. The groove 25 has a width of 2 mm to 5 mm and a depth of 1 to
It has a semicircular cross section of about 2.5 mm, and the interval between the grooves 25 is about 10 to 20 mm. The groove formed on the flange portion 23a communicates with the groove formed on the outer peripheral surface of the main body and the groove formed on the flange portion 23b to form one groove 25. In addition, the said protection pipe 2
No. 0 is integrally molded by using a mold in which a convex portion corresponding to the groove 25 is formed in advance.

With the above configuration, the airflow flowing along the protective tube 20 is such that the airflow sweeping the outer surface of the main body 21 and the airflow flowing through the groove 25 interfere with each other at the edge of the groove or at each peeling position. To form a turbulent boundary layer. For this reason, the occurrence of Karman vortices is suppressed, and the air resistance and air noise are reduced.

The cross-sectional shape of the groove 25 in this embodiment is a semicircular shape, but is not limited to this.
It can take various shapes such as a square shape. Also, the dimensions of the groove 25,
The spacing between the grooves 25 is not limited to the above dimensions, but may be appropriately selected according to the level of generated air noise or the like. Third Embodiment FIG. 3 is a perspective view of a protective tube 30 according to a third embodiment of the present invention.

The structure of the protection tube 30 is the same as that of the first embodiment except for the shape of the concave portion formed on the outer surface, and the description of the same components will be omitted. The protection tube 30 has a groove 35 formed in the outer surface of the main body 31 and the flange portions 33a and 33b, the groove 35 being parallel to the longitudinal direction. The groove 35 has a width of 2 mm to 5 mm and a depth of 1 to 2.5 mm
Formed in a semicircular cross-section of about
It is arranged so as to be about 0 to 20 mm. In addition,
The protective tube 30 is integrally formed by using a mold in which a convex portion corresponding to the groove 35 is formed on an inner surface in advance.

With the above configuration, the airflow flowing along the protective tube 30 is applied to the edge of the groove 35 (the outer surface of the main body 31 and the groove 35).
(Separation line), and the separated air flows interfere with each other to form a turbulent boundary layer on the outer surface of the protection tube 30, so that the generation of Karman vortices is suppressed. As a result, air resistance and air noise are reduced.

Although the cross-sectional shape of the groove 35 in this embodiment is a semicircular shape, it is not limited to this.
It can take various shapes such as a square shape. Also, the dimensions of the groove 35,
The spacing between the grooves 35 is not limited to the above-described size, but may be appropriately selected according to the level of generated air noise or the like. Fourth Embodiment FIG. 4 is a perspective view of a protection pipe 40 according to a fourth embodiment of the present invention.

The structure of the protection tube 40 is the same as that of the first embodiment except for the shape of the concave portion formed on the outer surface, and the description of the same components will be omitted. The protection tube 40 has a spline-shaped groove 45 provided on the outer surface of the main body 41 and the flange portions 43a and 43b.

That is, the protection tube 40 has a shape in which the outer surface of the protection tube 30 described in the third embodiment is twisted. The protective tube 40 is integrally formed by using a mold in which a convex portion corresponding to the groove 45 is formed in advance. As described above, by shifting the position of the separation point of the airflow flowing on the surface of the protection tube 40 on the circumference or on a plane, the effect of mutual interference of the separated airflows can be further enhanced. The generation of Karman vortices is suppressed. As a result, air resistance and air noise are reduced.

Although the cross-sectional shape of the groove 45 in this embodiment is a semicircle, it is not limited to this.
It can take various shapes such as a square shape. Also, the dimensions of the groove 45,
It goes without saying that the interval between the grooves 45 may be appropriately selected according to the level of the generated air noise or the like. [Fifth Embodiment] FIG. 5 is a perspective view of a protective tube 50 according to a fifth embodiment of the present invention.

The protection tube 50 is formed by providing a plurality of protrusions on the outer periphery thereof, contrary to the protection tube shown in the first to fourth embodiments. Other configurations are the same as those in the above-described embodiment, and the description of the same components will be omitted. Main body 51 of protective tube 50 and flange portions 53a, 53
A plurality of small piece pairs 55 are integrally erected on the outer surface of b. The small piece pair 55 is composed of a thin plate-shaped small piece 55a and a small piece 55b. The small pieces 55a and 55b
It is a substantially rectangular thin plate having a height of about 3 to 10 mm, a length of about 5 to 10 mm, and a width of about 1 to 2 mm, each of which is 5 to 15 mm each other.
They are arranged in a C-shape with an interval of mm.

The small piece pairs 55 are disposed at predetermined intervals (about 10 to 20 mm) in the longitudinal direction of the outer peripheral surface of the protective tube 50, and at predetermined intervals (about 5 to 10 mm) in the circumferential direction. Adjacent small piece pairs 55 are arranged such that the above-mentioned C-shaped characters are opposite to each other. The protective tube 50
Are integrally molded by using a mold in which a concave portion corresponding to the small piece pair 55 is formed in advance.

With the above configuration, the air flow flowing along the outer surface of the protection tube 50 is compressed and diffused when passing between the small pieces 55a and 55b of the small piece pair 55. And
This air flow may be between adjacent strip pairs 55, or
Since the turbulent boundary layer is formed by interfering with the air flow passing between the small pieces 55a and 55b of the adjacent small piece pair 55, the generation of Karman vortices is suppressed. As a result, air resistance and air noise are reduced.

The protection tube 50 of this embodiment may be configured such that the small pieces 55a and 55b are separately attached to the main body 51. Further, the shape of the small pieces 55a and 55b is not limited to the rectangular shape as described above, but may be another polygonal shape or a semicircular shape. Furthermore,
The small piece pair 55 is configured by arranging the small pieces 55a and 55b in a C shape, but may be arranged in parallel with each other. Furthermore, the dimensions of the small pieces 55a and 55b and the interval between them are not limited to those described above, and may be appropriately selected according to the level of the generated air noise or the like. Sixth Embodiment FIG. 6 is a perspective view of a protection tube 60 according to a sixth embodiment of the present invention.

The structure of the protection tube 60 is the same as that of the fifth embodiment except for the shape of the convex portion formed on the outer surface, and the description of the same components will be omitted. The protection tube 60 is configured such that a plurality of small conical protrusions 65 having a height of 3 to 10 mm are provided upright on the outer surfaces of the main body 61 and the flange portions 63a and 63b. The protective tube 60
Are integrally formed by using a mold in which the small projections 65 are formed in advance.

The air flow flowing along the outer surface of the protection tube 60 collides with the small projection 65 and locally changes its traveling direction. Due to this local turbulence, the surface boundary layer changes from a laminar boundary layer to a turbulent boundary layer. Therefore, the regular occurrence of Karman vortices is reduced, and the air resistance and aerodynamic noise are reduced.

In this embodiment, the small projections 65 are used.
Is a conical shape, but may be a hemispherical shape, a cubic shape, or a rectangular parallelepiped shape. The small projection 6
Of course, the size of 5 and the interval between the small protrusions 65 may be appropriately selected according to the level of the generated air noise and the like. Seventh Embodiment FIG. 7 is a perspective view of a protection pipe 70 according to a seventh embodiment of the present invention.

The structure of the protection tube 70 is the same as that of the fifth embodiment except for the shape of the convex portion formed on the outer surface, and the description of the same components will be omitted. The protective tube 70 is provided with a mesh-like projection 75 over the entire outer surfaces of the main body 71 and the flange portions 73a and 73b. Conditions such as the roughness of the mesh of the mesh-like projection 75 and the size of the projection 75 are appropriately adjusted in accordance with the level of aerodynamic noise generated at that portion. The protective tube 70 is integrally formed by using a mold in which a concave portion corresponding to the mesh projection 75 is formed in advance.

With the above configuration, the air flow flowing along the surface of the protection tube 70 causes small local separation via the mesh-like projections 75. Due to the turbulence of the airflow on the surface of the protection tube 70 due to the small separation, the boundary layer on the surface changes from a laminar boundary layer to a turbulent boundary layer. This eliminates the regular occurrence of Karman vortices, and reduces air resistance and aerodynamic noise.

The embodiment of the present invention is not limited to the above-described embodiment at all, and it goes without saying that the present invention can be implemented in various modes as long as it belongs to the technical scope of the present invention. For example, it is a matter of course that a configuration in which the above-described embodiments 1 to 7 are appropriately combined may be adopted.

[Brief description of the drawings]

FIG. 1 is a perspective view of a protective tube according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a protective tube according to a second embodiment of the present invention.

FIG. 3 is a perspective view of a protective tube according to a third embodiment of the present invention.

FIG. 4 is a perspective view of a protective tube according to a fourth embodiment of the present invention.

FIG. 5 is a perspective view of a protective tube according to a fifth embodiment of the present invention.

FIG. 6 is a perspective view of a protective tube according to a sixth embodiment of the present invention.

FIG. 7 is a perspective view of a protective tube according to a seventh embodiment of the present invention.

FIG. 8 is a perspective view of a conventional protective tube.

[Explanation of symbols]

10, 20, 30, 40, 50, 60, 70 ... wire protective tube, 11, 21, 31, 41, 51, 61, 71
..Main bodies, 13a, 23a, 33a, 43a, 53a,
63a, 73a: flange portion, 13b, 23b, 3
3b, 43b, 53b, 63b, 73b: Flange, 15: Dimple, 17: Split, 2
5, 35, 45 ... groove, 55 ... small piece pair, 55
a, 55b ... small piece, 65 ... small projection, 75 ...
・ Reticulated protrusion

Claims (10)

[Claims] 1. A main body having a cylindrical long axis shape having a cut in a lower longitudinal direction, and a pair of flange portions extending vertically downward from both end edges of the split, between the pair of flange portions. An electric wire protection tube for drawing an electric wire from a main body and holding the electric wire in the main body, wherein a plurality of recesses are provided on outer surfaces of the main body and the flange portion. 2. The electric wire protection tube according to claim 1, wherein the recess is formed in a dimple shape. 3. The concave portion includes a groove formed in the main body in a circumferential direction perpendicular to a longitudinal direction of the main body, and a groove formed in the flange portion in a direction extending from the main body. The electric wire protective tube according to claim 1, wherein the electric wire protective tube is configured. 4. The wire protection tube according to claim 1, wherein the recess is formed by a groove formed in parallel with the longitudinal direction of the main body and the flange. 5. The electric wire protection tube according to claim 1, wherein the recess is formed by a spiral groove. 6. A main body having a cylindrical longitudinal axis shape having a lower longitudinally cleft, and a pair of flanges extending vertically downward from both ends of the crevice, between the pair of flanges. An electric wire protection tube, wherein a plurality of protrusions are provided on outer surfaces of the main body and the flange portion, the electric wire protection tube being adapted to draw in an electric wire from the main body and hold the electric wire in the main body. 7. The electric wire protective tube according to claim 6, wherein the convex portion is constituted by a pair of small pieces formed by erecting two thin plate-shaped small pieces. 8. The electric wire protection tube according to claim 6, wherein the projection is formed by a conical small projection. 9. The electric wire protection tube according to claim 6, wherein the projection is formed by a mesh-like projection formed in a mesh. 10. The small piece pair, wherein the two small pieces are formed upright in a C-shape.
Wire protection tube as described.