JP2007262785A - Metal pipe column and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal pipe column which can curb increase in the manufacturing cost and can be installed on a road side or in a park without causing a safety problem. <P>SOLUTION: The metal pipe column 10 comprises a column body 11 formed with a tapered metal pipe, a base plate 12 having a pipe-shaped part 12a externally fitted to a base end part of the column body 11, and an inside reinforcing pipe 13 internally fitted to a base end part of the column body 11. An inner peripheral surface of the pipe-shaped part 12a of the base plate 12 is friction-joined to an outer peripheral surface of the column body 11, and an outer peripheral surface of the inside reinforcing pipe 13 is friction-joined to an inner peripheral surface of the column body 11 in a manner of overlapping the pipe-shaped part 12a of the base plate 12. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a metal tube column and a method of manufacturing the same, such as for installation of equipment such as a camera, a microphone, a speaker, etc., for lighting, or for signs, such as a street, an elevated road, a roadside, a park, and the like.

  The metal tube struts erected on the side of the road or in the park support relatively light equipment such as lights and signs at a height of several meters, and the outer diameter is about 5 to 50 cm. It is said that. In addition, unlike general construction structural members, metal tube struts do not receive a large load from above. For example, in the case of steel tube struts, the road lighting equipment specifications of the Japan Construction Electrical Engineering Association As defined in the standards, those with a wall thickness of about 3 to 9 mm are used. In addition, since metal pipe columns are used in locations exposed to wind and rain, a design that can maintain sufficient strength to prevent the base of the column from breaking or collapsing due to lateral loads caused by wind or traffic vibrations. Has been made. In addition, the outer diameter of the metal tube support is generally provided with a taper of about 1/100 to 1/75, and is a tapered tube with a tapered tip.

  A typical example of a conventional metal tube support is shown in FIG. As shown in FIG. 6, a base plate 5 that supports the column main body 1 is engaged with and joined to the lower end portion of the column main body 1 made of a metal tube such as a steel pipe. Here, the column main body 1 is inserted into, for example, a hole formed in the base plate 5 and joined by welding a portion indicated by 2b in the circumferential direction. However, as a method of joining the column main body 1 and the base plate 5, there is a method in which the lower end portion of the column main body 1 and the upper surface portion of the base plate 5 are welded and joined.

  The base plate 5 is provided with a required number of anchor mounting holes 6 for installation and fixing. Furthermore, a required number of vertical ribs 4 are arranged in the vertical direction from the base plate 5 to the lower part of the column main body 1. Since the vertical ribs 4 are required to have a structure that can withstand loads from the four sides of the column main body 1, at least four, and in some cases, six to eight are provided at equal intervals in the circumferential direction of the column main body. In general, the vertical rib 4 and the column main body 1 and the base plate 5 are joined by welding.

  In the metal pipe column shown in FIG. 6, when a lateral load due to wind force, traffic vibration, or the like repeatedly acts for many years, there is a possibility that a crack based on fatigue may occur at the upper end weld portion (position 2a shown in FIG. 6) of the vertical rib. Is expensive. This is because, when a lateral load is applied to the metal tube strut, the stress generated thereby is concentrated on the welded portion 2a at the upper end, and the welded portion 2a that is the fillet weld toe at the upper end of the vertical rib is the stress concentrated portion. This is because it becomes 3.

As a result of numerical analysis using the FEM (finite element method) on the stress generated in the vicinity of the vertical rib provided at the base portion of the metal tube support column, the upper end of the vertical rib is about 4 in comparison with the case without the vertical rib. It became clear that about twice the stress concentration occurred.
Moreover, since the upper end portion of the vertical rib is usually welded, if there is a weld defect, if the above stress concentration occurs, cracks are likely to occur due to the stress concentration. Even if there is no weld defect, if stress is repeatedly applied, the possibility of fatigue failure increases.

Therefore, the upper end of the outer tube fitted to the base end of the column main body and the column main body are left in a free state without welding and the lateral load applied to the column main body is between the column main body and the outer tube. The outer tube is transferred to the base plate through a non-shrinkable cement, epoxy resin, or other filler (see Patent Document 1), or the base end of the column body is not welded to the base plate. A device that is supported by a support tube (see Patent Document 2) has been devised.
JP 2002-129778 A (page 3, left column, line 41-page 4, left column, line 34, FIG. 1) JP 2003-49561 (page 3, right column, lines 17-39, FIG. 1)

However, the metal pipe column shown in the above-mentioned document 1 requires skilled skills when filling a filler between the column body and the outer tube. For this reason, it is difficult to efficiently fill the filler between the column main body and the outer tube, and the filling work of the filler requires a lot of time and labor, leading to an increase in construction cost.
On the other hand, in the metal pipe support shown in the above-mentioned document 2, the above-mentioned problems do not occur, but when installed on a sidewalk near a roadside or in a park, the vertical ribs provided around the exterior support pipe are not attached. There is a risk that a safety problem such as a fall accident may occur due to being caught.
The present invention has been made paying attention to the above-mentioned problems, and its purpose is to suppress an increase in manufacturing cost and to be installed on the side of a road or in a park without causing a safety problem. An object of the present invention is to provide a metal tube strut that can be used and a method of manufacturing the same.

  In order to solve the above-mentioned problem, a metal tube strut according to a first aspect of the present invention includes a column main body made of a tapered metal tube, a base plate having a tubular portion that is fitted on a base end portion of the column main body, and the column main body. And an inner reinforcing pipe fitted inside, the inner peripheral surface of the tubular portion is friction-bonded to the outer peripheral surface of the column main body, and the outer peripheral surface of the inner reinforcing pipe is the base plate It is characterized in that it is friction bonded to the inner peripheral surface of the column main body so as to overlap the tubular portion.

  A metal pipe column according to a second aspect of the present invention is a column main body made of a tapered metal tube, a base plate having a tubular portion fitted inside the base end portion of the column main body, and a base end portion of the column main body. An outer reinforcing tube, and the outer peripheral surface of the tubular portion is frictionally joined to the inner peripheral surface of the column main body, and the inner peripheral surface of the outer reinforcing tube overlaps the tubular portion of the base plate. It is characterized in that it is friction bonded to the outer peripheral surface of the column main body.

  According to a third aspect of the present invention, there is provided a metal tube strut manufacturing method comprising: a strut body made of a tapered metal tube; a base plate having a tubular portion that is fitted on a base end portion of the strut body; and a base end portion of the strut body. A metal tube strut joining method comprising an inner reinforcing tube fitted inside, wherein the inner reinforcing tube is press-fitted into a base end portion of the strut body, and an outer peripheral surface of the inner reinforcing tube is connected to an inner side of the strut body. The outer peripheral surface of the column main body and the inner peripheral surface of the tubular portion are friction bonded together with the peripheral surface.

  According to a fourth aspect of the present invention, there is provided a metal tube strut manufacturing method comprising: a strut body made of a tapered metal tube; a base plate having a tubular portion fitted into a base end portion of the strut body; and a base end portion of the strut body. A metal tube strut joining method comprising an outer reinforcing tube that fits externally, wherein the outer reinforcing tube is press-fitted into a base end portion of the strut body, and an inner peripheral surface of the outer reinforcing tube is connected to the strut body. The outer peripheral surface is friction bonded and the inner peripheral surface of the column main body and the outer peripheral surface of the tubular portion are friction bonded.

  According to the metal tube strut according to the first invention, in order to suppress the occurrence of fatigue failure due to stress concentration, it is necessary to fill a filler such as non-shrinkage cement or epoxy resin between the strut body and the tubular portion of the base plate. Since there is no, an increase in manufacturing cost can be suppressed. Moreover, since it is not necessary to erect a plurality of ribs on the base plate, it can be installed on the roadside or in a park without causing a safety problem. Furthermore, since the base end portion of the column main body is joined to the tubular portion of the base plate by a method other than welding, the occurrence of cracks due to stress concentration can be reduced. Furthermore, since the outer peripheral surface of the inner reinforcing tube is friction bonded to the inner peripheral surface of the column main body so that it overlaps the tubular portion of the base plate, the joint between the base end of the column main body and the tubular portion of the base plate is internally reinforced. The tube can be reinforced strongly, and thereby the occurrence of fatigue failure due to repeated stress can be reduced.

  According to the metal pipe column according to the second invention, in order to suppress the occurrence of fatigue failure due to stress concentration, it is necessary to fill a filler such as non-shrinkage cement or epoxy resin between the column body and the outer reinforcing tube. Therefore, an increase in manufacturing cost can be suppressed. Moreover, since it is not necessary to erect a plurality of ribs on the base plate, it can be installed on the roadside or in a park without causing a safety problem. Furthermore, since the base end portion of the column main body is joined to the tubular portion of the base plate by a method other than welding, the occurrence of cracks due to stress concentration can be reduced. Furthermore, since the inner peripheral surface of the outer reinforcing pipe is frictionally joined to the outer peripheral surface of the column main body so as to overlap the tubular portion of the base plate, the occurrence of fatigue failure due to repeated stress can be reduced.

Hereinafter, a metal pipe support according to the present invention will be described with reference to the drawings.
One embodiment of a metal pipe column according to the first invention is shown in FIG. As shown in the figure, the metal pipe column 10 includes a column main body 11 made of a tapered metal tube (for example, a steel pipe having a taper of about 1/100 to 1/75), and a base end portion of the column main body 11. And a metal base plate 12 having a tubular portion 12a to be fitted externally. The inner peripheral surface of the tubular portion 12a is frictionally joined to the outer peripheral surface of the base end portion of the column main body 11. In addition, the metal tube support column 10 includes a metal inner reinforcing portion 13 that fits inside the base end portion of the column main body 11, and the outer peripheral surface of the inner reinforcement tube 13 overlaps the tubular portion 12 a of the base plate 12. 11 is friction bonded to the inner peripheral surface of the base end portion.

  An example of a method for manufacturing the metal pipe support shown in FIG. 1 is shown in FIG. As shown in FIG. 2, when manufacturing the metal pipe support shown in FIG. 1, first, the support main body 11 is placed in the tubular portion 12a of the base plate 12 as shown in FIGS. 2 (a) and 2 (b). Inserted from the distal end side, the outer peripheral surface of the base end portion of the column main body 11 is fitted to the inner peripheral surface of the tubular portion 12a. Next, as shown in FIGS. 2 (c) and 2 (d), the upper end of the tubular portion 12 a is pressed by the stopper 14, and in this state, the inner reinforcing pipe 13 is placed in the base end portion of the column main body 11 and the hydraulic pressure of the hydraulic cylinder 15. Press fit with. Then, the outer peripheral surface of the inner reinforcing tube 13 is crimped (friction bonded) to the inner peripheral surface of the base end portion of the column main body 11, and the inner peripheral surface of the tubular portion 12 a of the base plate 12 is the outer peripheral surface of the base end portion of the column main body 11. Crimped (friction bonded) to

  In the metal tube strut 10 configured as described above, a filler such as non-shrinkable cement or epoxy resin is provided between the strut body 11 and the tubular portion 12a of the base plate 12 in order to suppress the occurrence of fatigue failure due to stress concentration. Since it is not necessary to fill, an increase in manufacturing cost can be suppressed. Moreover, since it is not necessary to erect a plurality of ribs on the base plate 12, it can be installed on the roadside or in a park without causing a safety problem. Furthermore, since the base end portion of the column main body 11 is joined to the tubular portion 12a of the base plate 12 by a method other than welding, the occurrence of cracks due to stress concentration can be reduced. Furthermore, since the outer peripheral surface of the inner reinforcing tube 13 is frictionally joined to the inner peripheral surface of the column main body 11 so as to overlap the tubular portion 12a of the base plate 12, the base end portion of the column main body 11 and the tubular portion 12a of the base plate 12 are joined. Can be firmly reinforced by the inner reinforcing tube 13, thereby reducing the occurrence of fatigue failure due to repeated stress.

  In addition, since friction joining is simultaneously performed on the inner peripheral surface of the base end portion and the outer peripheral surface of the base end portion of the column main body 11, the base end portion of the column main body 11 may expand in the outer diameter direction or be narrowed in the inner diameter direction. Since the metal tube strut can be manufactured without giving deformation or buckling to the base end portion of the strut body 11, the strength of the strut body 11 is not adversely affected.

  Next, FIG. 3 shows an embodiment of a metal tube support according to the second invention. As shown in the figure, the metal pipe column 20 includes a column main body 21 made of a tapered metal tube (for example, a steel pipe having a taper of about 1/100 to 1/75), and a base end portion of the column main body 21. A metal base plate 22 having a tubular portion 22 a to be fitted therein is provided, and the outer peripheral surface of the tubular portion 22 a is friction bonded to the inner peripheral surface of the base end portion of the column main body 21. In addition, the metal pipe column 20 includes a metal outer reinforcing portion 23 that is fitted on the base end portion of the column main body 21, and the outer peripheral surface of the outer reinforcing tube 23 overlaps the tubular portion 22 a of the base plate 22. 21 is friction bonded to the outer peripheral surface of the base end portion.

  An example of a method for manufacturing the metal tube support shown in FIG. 3 is shown in FIG. When manufacturing the metal tube support shown in FIG. 3, as shown in FIGS. 4A and 4B, first, the outer peripheral surface of the base end portion of the support main body 21 is the inner periphery of the tubular portion 22 of the base plate 22. Insert into the surface. Next, as shown in FIG. 4C, after the outer reinforcing tube 23 is inserted from the front end side of the column main body 21, as shown in FIGS. 4D and 4E, the lower surface portion of the base plate 22 is stopped by the stopper. The outer reinforcing tube 23 is pushed into the outer periphery of the base end portion of the column main body 21 from the distal end side of the column main body 21 with the hydraulic pressure of the hydraulic cylinder 25 while being supported by 24. Then, the inner peripheral surface of the outer reinforcing tube 23 is crimped (friction bonded) to the outer peripheral surface of the base end portion of the column main body 21, and the inner peripheral surface of the base end portion of the column main body 21 is the outer peripheral surface of the tubular portion 22 a of the base plate 22. Crimped (friction bonded) to

  In the metal tube strut 20 configured as described above, a filler such as non-shrinkable cement or epoxy resin is filled between the strut body 21 and the outer reinforcing tube 23 in order to suppress the occurrence of fatigue failure due to stress concentration. Since it is not necessary, an increase in manufacturing cost can be suppressed. Moreover, since it is not necessary to erect a plurality of ribs on the base plate 22, it can be installed on the roadside or in a park without causing a safety problem. Furthermore, since the base end portion of the column main body 21 is joined to the tubular portion 22a of the base plate 22 by a method other than welding, the occurrence of cracks due to stress concentration can be reduced. Furthermore, since the inner peripheral surface of the outer reinforcing tube 23 is friction bonded to the outer peripheral surface of the column main body 21 so as to overlap the tubular portion 22a of the base plate 22, the occurrence of fatigue failure due to repeated stress can be reduced. Further, similarly to the example shown in FIG. 2, since the friction bonding is performed without adversely affecting the strength of the column main body 21, a metal tube column having a stable quality can be obtained.

  In the embodiment described above, the metal tube column 20 is manufactured by pushing the outer reinforcing tube 23 into the outer periphery of the base end of the column main body 21 with the hydraulic pressure of the hydraulic cylinder 25 while supporting the lower surface of the base plate 22 with the stopper 24. However, as shown in FIG. 5, after inserting the column main body 21 into the outer reinforcing tube 23 from the distal end side, the base plate 12 is inserted into the base end of the column main body 11 while pressing the upper end of the outer reinforcing tube 23 with the stopper 24. The tubular portion 12a may be press-fitted with the hydraulic pressure of the hydraulic cylinder 25.

Table 1 shows the results of a fatigue test of the metal tube strut (weld joint type) shown in FIG. 6 and the metal tube strut (friction joint type) shown in FIGS. 1 and 3 under the following test conditions.
[Fatigue test conditions]
(1) Test method (a) Test equipment used: 50-ton electro-hydraulic servo-type fatigue tester (b) Displacement was controlled by a double-load (tension-compression) loading method using two simultaneous loading methods.
(C) Prior to repeated loading, a static loading test is performed to measure the stress distribution in the vicinity of the stress concentration part of the upper and lower surfaces where the maximum stress occurs, and after the fatigue test is started, a static loading test is performed as appropriate. The change of stress distribution in the same part with repetition was measured and recorded.

(2) Specimen dimensions Metal tube strut: outer diameter 188 mm (inner diameter 172 mm) x thickness 6 mm x length 1630 mm, 2 pieces (black tube product): No. 1-2 specimen Metal tube strut: outer diameter 188 mm (inner diameter) 174mm) x thickness 8mm x length 1630mm, 2 pieces (hot dip galvanized product): No. 3-4 test specimens Column body material: SS400 (1/100 taper pipe), inner / outer reinforcement pipe material: STM13A
(3) Fatigue life Fatigue life is 95% (at 5% down) from the initial stress value.

From the fatigue test results shown in Table 1, in the conventional type (welded joint type) metal pipe strut, cracks occurred in the welded portion of the longitudinal rib when the number of tests reached 1.31 × 10 ⁴ with a stress amplitude of 83 MPa. . On the other hand, it was found that the friction-joint type metal tube struts did not crack even when the number of tests reached 2.19 × 10 ⁶ with a stress amplitude of 203 MPa, and this confirmed that fatigue strength could be improved. did it.

It is sectional drawing which shows one Embodiment of the metal pipe support | pillar which concerns on 1st invention. It is a figure which shows an example of the manufacturing method of the metal pipe support | pillar shown in FIG. It is sectional drawing which shows one Embodiment of the metal pipe support | pillar which concerns on 2nd invention. It is a figure which shows an example of the manufacturing method of the metal pipe support | pillar shown in FIG. It is a figure which shows the other example of the manufacturing method of the metal pipe support | pillar shown in FIG. It is a half sectional view showing a conventional metal pipe support.

Explanation of symbols

11, 21 Prop body 12, 22 Base plate 12a, 22a Tubular part 13 Inner reinforcement pipe 23 Outer reinforcement pipe

Claims (4)

  A column main body comprising a tapered metal tube, a base plate having a tubular portion fitted around the base end portion of the column main body, and an inner reinforcing tube fitted inside the base end portion of the column main body, The inner peripheral surface of the column is friction bonded to the outer peripheral surface of the column main body, and the outer peripheral surface of the inner reinforcing tube is friction bonded to the inner peripheral surface of the column main body so as to overlap the tubular portion of the base plate. Metal tube strut characterized by that.   A column main body comprising a tapered metal tube, a base plate having a tubular portion fitted inside the base end portion of the column main body, and an outer reinforcing tube fitted outside the base end portion of the column main body, The outer peripheral surface of the portion is friction bonded to the inner peripheral surface of the column main body, and the inner peripheral surface of the outer reinforcing tube is friction bonded to the outer peripheral surface of the column main body so as to overlap the tubular portion of the base plate. Metal tube strut characterized by that.   A metal tube column comprising a column main body made of a tapered metal tube, a base plate having a tubular portion that is fitted around the base end portion of the column main body, and an inner reinforcing tube fitted inside the base end portion of the column main body. The inner reinforcing tube is press-fitted into the base end portion of the column main body, and the outer peripheral surface of the inner reinforcing tube is frictionally bonded to the inner peripheral surface of the column main body and the outer peripheral surface of the column main body. And a method of manufacturing a metal tube strut, characterized by friction-joining an inner peripheral surface of the tubular portion.   A metal tube column comprising a column main body made of a tapered metal tube, a base plate having a tubular portion fitted inside the base end portion of the column main body, and an outer reinforcing tube fitted outside the base end portion of the column main body. The outer reinforcing pipe is press-fitted into the base end portion of the column main body, and the inner peripheral surface of the outer reinforcing tube is friction-bonded to the outer peripheral surface of the column main body and the inner periphery of the column main body. A method of manufacturing a metal tube strut, wherein the surface and the outer peripheral surface of the tubular portion are friction-joined.

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