JP5430201B2 - Columnar tube with holes - Google Patents

Description

  The present invention relates to a columnar tube with a hole that can effectively prevent the generation of feedback oscillation sound.

As a columnar tube (pipe) closed at both ends, used as a member that forms a truss structure, a temporary frame scaffold, an overhead wire support member, a support tube, etc., the peripheral wall of the columnar tube is provided with a plurality of holes penetrating inside and outside the tube A columnar tube with a hole is known (see, for example, Patent Document 1).
The plurality of holes are used for applying plating to the inside of the columnar tube, for draining rain, for bolting, and the like.
For example, as shown in FIG. 9, the conventional columnar tube with holes 1 </ b> A includes two holes 5; 5 having a center line 4 as one line orthogonal to the center line 3 of the tube 2 in the peripheral wall 21 of the tube 2. As shown in FIG. 10, the hole 5 penetrates the outer surface 22 and the inner surface 23 of the peripheral wall 21.

JP-A-7-178858

In the case of the conventional holed columnar tube 1A, as shown in FIG. 10, when the direction of the wind F intersects the center line 4 of the hole 5 (for example, orthogonal), the edge of the hole where the wind F separates from the tube 2 ( At the edge (A), the wind vortex F1 is released, and the vortex F1 rides on the wind flow and collides with the hole edge (edge) B on the downstream side to generate sound, and the pressure wave F2 generated here is upstream. When the phenomenon of propagating to the hole edge A and creating the next vortex F1 is periodically repeated, a so-called feedback oscillation sound (wind noise) is generated. Conventionally, since the center line 4 of the two holes 5; 5 is the same in the columnar tube 1A with holes, as described above, for example, the wind F in the direction intersecting the center line 4 of the two holes 5; When blown, feedback oscillation sounds are generated in the two holes 5;
Therefore, the present invention provides a columnar tube with a hole that can effectively prevent the generation of feedback oscillation sound.

Slotted cylindrical tube according to the present invention includes: a hole formed so as to penetrate into and out of the tube wall of which is formed into a circular cross section tube, and the projecting portion of the annular surrounding the hole to protrude from the outer surface of the peripheral wall The projecting portion is a columnar tube with a hole provided at a distance from the periphery of the hole, and the annular projecting portion is an annular body formed of a flat plate having a predetermined thickness, and the outer surface of the tube. The ring is bent so that the center line of the circle and the center line of the hole coincide with each other. By forming the inner surface joined to the outer surface of the tube, the inner peripheral surface rising from the outer surface of the tube, the outer peripheral surface rising from the outer surface of the tube, the rising end of the inner peripheral surface, and the outer peripheral surface And an annular surface connecting the rising end of the annular projection, and an inner peripheral surface of the annular protrusion Since the dimension of the width of the annular surface of the hole around which connect the periphery of the hole and up starting end are equal, periodic wind is released from the outer peripheral edge of the annular surface of the projecting portion collides with the outer peripheral surface of the projecting portion The wind vortex collides with the wind that collides with the annular surface around the hole after colliding with the inner peripheral surface of the protrusion, and the wind vortex breaks, causing periodic oscillation that is the cause of feedback oscillation sound It is possible to reduce the vortex of the wind and effectively prevent the generation of feedback oscillation sound.
Since the height of the protrusion is 3.85 mm or more and 10 mm or less, the generation of feedback oscillation sound can be more effectively prevented.
Since the distance between the rising start edge of the inner peripheral surface of the protrusion and the peripheral edge of the hole is 2 mm or more and 8 mm or less, the generation of feedback oscillation sound can be more effectively prevented.

Sectional drawing of a columnar pipe with a hole. The perspective view of a columnar pipe with a hole. The figure which shows the kind of test body of the columnar pipe with a hole used for experiment. The figure which shows an experimental result. The figure which shows an experimental result. The figure which shows an experimental result. The figure which shows an experimental result. The figure which shows an experimental result. The perspective view of a columnar pipe with a hole (conventional). The figure explaining the generation principle of feedback oscillation sound (conventional).

  As shown in FIG. 2, the columnar tube 1 with a hole includes a metal tube 2 formed in a circular cross section with both ends closed, and a peripheral wall 2 a of the tube 2 so as to penetrate the inner surface 23 and the outer surface 22 of the tube 2. And an annular projecting portion 6 that projects from the outer surface 22 of the tube 2 and surrounds the hole 5, and the projecting portion 6 is provided away from the peripheral edge 15 of the hole 5.

  The annular protrusion 6 is formed so that the center line of the circle of the torus and the center line 4 of the hole 5 coincide. The annular protrusion 6 is formed by pressing, for example, an unillustrated annular body (ring) formed of a metal flat plate having a predetermined thickness with an unillustrated press die having the same surface as the outer surface 22 of the tube 2. As shown in FIG. 1, the outer surface 22 and the torus are formed in a state where the curved inner surface 12 of the curved torus is in contact with the outer surface 22 of the tube 2 as shown in FIG. 1. It can be formed by joining by welding or the like.

  As shown in FIG. 1, an annular projecting portion 6 (hereinafter referred to as a ring projecting portion 6) formed by joining the curved inner surface 12 of the torus to the outer surface 22 of the tube 2 is more than the outer surface 22 of the tube 2. An inner peripheral surface 10 of the rising ring, an outer peripheral surface 11 of the ring rising from the outer surface 22 of the pipe 2, and an annular surface 13 connecting the rising end 10a of the inner peripheral surface 10 and the rising end 11a of the outer peripheral surface 11. Prepare.

The height (= rising dimension of the outer peripheral surface 11 and the inner peripheral surface 10) H (hereinafter referred to as ring height H) of the ring protrusion 6 is set to 3.85 mm or more and 10 mm or less based on the experimental results described later.
The distance between the rising start edge 10b of the inner peripheral surface 10 of the ring protrusion 6 and the peripheral edge 15 of the hole 5 (= connecting the rising start edge 10b of the inner peripheral surface 10 of the ring protrusion 6 and the peripheral edge 15 of the hole 5). The width dimension L of the annular surface 14 around the hole (hereinafter referred to as the width L of the annular surface inside the ring) is 2 mm or more and 8 mm or less based on the experimental results described below.
The distance between the rising end 10a of the inner peripheral surface 10 of the ring protrusion 6 and the rising end 11a of the outer peripheral surface 11 (= the width dimension of the annular surface 13 of the ring protrusion 6) W (hereinafter referred to as the ring width W). Is 4 mm or more and 8 mm or less.

According to the columnar tube 1 with a hole of this embodiment, the ring-shaped ring protrusion 6 having a configuration that protrudes from the outer surface 22 of the tube 2 to surround the hole 5 and is provided away from the peripheral edge 15 of the hole 5 is provided. Therefore, the wind collides with the outer peripheral surface 11 of the ring protrusion 6 and the periodic wind vortex discharged from the outer peripheral edge (rising end 11a) of the annular surface 13 of the ring protrusion 6 and the ring protrusion 6 After colliding with the inner peripheral surface 10 and colliding with the annular surface 14 around the hole and turning back, the periodic wind vortex is broken, so the periodic wind that is the cause of the generation of feedback oscillation sound Vortices can be reduced, and the generation of feedback oscillation noise can be effectively prevented.
Since the ring protrusion 6 is formed in an annular shape, the shape of the inner peripheral surface 10 of the ring protrusion 6 is equal, and the width L of the annular surface 14 inside the ring is also equal. An equal effect is obtained with respect to wind in all directions orthogonal to 4.
Since the width L of the annular surface 14 inside the ring is provided, the effect of turning back the wind that collides with the annular surface 14 around the hole is ensured, and the periodic wind vortex that is the cause of the generation of feedback oscillation sound is further reduced. Since it can be reduced, the generation of feedback oscillation sound can be more effectively prevented.

The effect of the columnar tube 1 with a hole of the form 1 was confirmed by experiment.
In FIG. 3, the kind of test body of the columnar pipe 1 with a hole used for experiment is shown. A wind tunnel experiment was conducted for each of these specimens, and a Fourier analysis of the sound produced for each specimen was performed to determine the A characteristic corrected sound pressure level of the generated sound. The experimental results are shown in FIGS. The experiment was performed by applying a wind of 9 m / s to the test body. Further, the crossing angle α between the wind direction and the center line 4 of the hole 5 was unified for each group classified by (a); (b); (c); (d) in FIG. Specifically, α = 90 ° is set in the group (a) of FIG. 3, α = 58 ° is set in the groups (b) and (c) in FIG. 3, and α = is set in the group (d) in FIG. The angle was 60 °. Moreover, the test body used by the group of (a); (b); (c) of FIG. 3 was equipped with four holes 5 like the columnar tube 1 with a hole shown in FIG. The test body used in the group (d) is provided with only the solid-line hole 5 or the broken-line hole 5 of the columnar tube 1 with a hole shown in FIG. In the experiment, the tube 2 having a diameter of 60.5 mm, a length of 1100 mm, a thickness of the peripheral wall 2a of 3.8 mm, and a diameter of the hole 5 of 14 mm was used. In addition, in the comparison of the experimental result of each test body mentioned later, when the difference was less than ± 3 dB, it was not evaluated as the experimental error range.

  No. shown in FIG. The test specimen 1 is a columnar tube with a hole having a conventional configuration that does not include the ring protrusion 6 as shown in FIG. No. No. 110 specimen, no. The test body 113 is a columnar tube 1 with a hole of the present invention provided with a ring protrusion 6 as shown in FIG. Such no. No. 1 specimen, no. No. 110 specimen, no. The A characteristic correction sound pressure level of the 113 specimens was obtained, and the difference in the effect due to the presence or absence of the ring protrusion 6 was confirmed. 4A to 4C show the results of obtaining the A characteristic correction sound pressure level of each specimen shown in FIG.

As shown in FIG. According to the test results of the test piece 1, the sound pressure level at the dominant frequency is 62.4 dB at 306 Hz, 69.2 dB at 344 Hz, 71.7 dB at 447 Hz, 66.9 dB at 600 Hz, 51.4 dB at 752 Hz, 1200 Hz. 50.2 dB at 1800 Hz and 56.6 dB.
On the other hand, as shown in FIG. According to the experimental results of 110 specimens, the sound pressure level at the dominant frequency is 44.3 dB at 306 Hz, 63.0 dB at 344 Hz, 39.8 dB at 447 Hz, 50.2 dB at 600 Hz, 40.5 dB at 752 Hz, 1200 Hz. 37.9 dB at 1800 Hz.
Therefore, no. According to the 110 specimen, no. The sound pressure level at the dominant frequency is reduced by 18.1 dB at 306 Hz, 6.2 dB at 344 Hz, 31.9 dB at 447 Hz, 16.7 dB at 600 Hz, and 752 Hz. It can be seen that it decreased by 10.9 dB, decreased by 12.3 dB at 1200 Hz, and decreased by 18.4 dB at 1800 Hz.

Further, as shown in FIG. According to the test results of 113 specimens, the sound pressure level at the dominant frequency is 45.9 dB at 306 Hz, 62.8 dB at 344 Hz, 39.1 dB at 447 Hz, 63.4 dB at 600 Hz, 40.5 dB at 752 Hz, 1200 Hz. And 48.9 dB at 1800 Hz.
Therefore, no. According to the test body No. 113, no. The sound pressure level at the dominant frequency is 16.5 dB at 306 Hz, 6.4 dB at 344 Hz, 32.6 dB at 447 Hz, 3.5 dB at 600 Hz, and 752 Hz at 752 Hz. It can be seen that it decreased by 10.9 dB, decreased by 4.8 dB at 1200 Hz, and decreased by 7.7 dB at 1800 Hz.

  Therefore, the ring protrusion 6 is provided, the ring width (W) of the ring forming the ring protrusion 6 is 4.5 mm, the width (L) of the annular surface inside the ring is 3.5 mm, and the ring height (H). Is at least 4.5 mm or 6.0 mm. Compared with a columnar tube with a hole having a conventional structure that does not have the ring protrusion 6 as in the test body 1, the resonance in the tube 2 can be suppressed, the generated sound in the tube 2 can be reduced, and the feedback oscillation sound can be reduced. It turned out that it becomes the columnar pipe 1 with a hole which can prevent generation | occurrence | production more effectively. Accordingly, the columnar tube 1 with a hole having a ring height (H) and a ring width (W) and having a ring protrusion 6 that forms the width (L) of an annular surface inside the ring is a ring protrusion. It is considered that the generation of feedback oscillation sound can be more effectively prevented as compared to a columnar tube with a hole having a conventional configuration that does not include the portion 6.

Each specimen No. shown in FIG. 90, no. 91, no. 92, the difference in the effect by the difference in the ring height (H) of the ring protrusion part 6 was confirmed. The results of obtaining the A-characteristic corrected sound pressure level of each specimen shown in FIG. 3B are shown in FIGS.
As shown in FIG. According to the experimental results of 90 specimens, the sound pressure level of the dominant frequency is 50.2 dB at 242 Hz, 66.6 dB at 295 Hz, 49.5 dB at 352 Hz, 52.7 dB at 541 Hz, 47.2 dB at 1499 Hz, 1798 Hz. 54.3 dB at 1886 Hz and 50.3 dB at 1886 Hz.
On the other hand, as shown in FIG. According to the experimental results of 91 specimens, the sound pressure level at the dominant frequency is 43.5 dB at 242 Hz, 40.5 dB at 295 Hz, 40.5 dB at 352 Hz, 40.3 dB at 541 Hz, 36.9 dB at 1499 Hz, 1798 Hz. 36.4 dB at 1886 Hz and 34.9 dB at 1886 Hz.
Therefore, no. According to the test body No. 91, no. Compared to 90 specimens, the sound pressure level at the dominant frequency decreased by 6.7 dB at 242 Hz, decreased by 26.1 dB at 295 Hz, decreased by 9.0 dB at 352 Hz, decreased by 12.4 dB at 541 Hz, and at 1499 Hz. It can be seen that it decreased by 10.3 dB, decreased by 17.9 dB at 1798 Hz, and decreased by 15.4 dB at 1886 Hz.

Further, as shown in FIG. According to the experimental results of 92 specimens, the sound pressure level at the dominant frequency is 36.7 dB at 242 Hz, 39.6 dB at 295 Hz, 40.6 dB at 352 Hz, 42.4 dB at 541 Hz, 36.2 dB at 1499 Hz, 1798 Hz. 36.9 dB at 1886 Hz and 33.0 dB at 1886 Hz.
Therefore, no. According to the specimen No. 92, no. Compared to 90 specimens, the sound pressure level at the dominant frequency is 13.5 dB at 242 Hz, 27.0 dB at 295 Hz, 8.9 dB at 352 Hz, 10.3 dB at 541 Hz, 11.0 dB at 1499 Hz, 17.75 at 1798 Hz. It can be seen that there was a decrease of 17.3 dB at 4 dB and 1886 Hz.

  From the above results, it can be inferred that by setting the ring height (H) of the ring protrusion 6 to 3.2 mm or more, a holed columnar tube 1 that can effectively prevent the generation of feedback oscillation sound can be obtained. From this result, it was found that by setting the ring height H of the ring protrusion 6 to 4.5 mm or more and 6 mm or less, the columnar tube 1 with a hole that can more effectively prevent the generation of feedback oscillation sound can be obtained. .

Differences in effects due to differences in the width (L) of the ring-shaped annular surface inside the ring were confirmed using the test specimens shown in FIG. The results of obtaining the A characteristic corrected sound pressure level of each specimen shown in FIG. 3B are shown in FIGS. 6A and 6B and FIGS. 7A to 7C.
As shown in FIG. According to the test results of 95 specimens, the sound pressure level at the dominant frequency was 56.8 dB at 644 Hz, 38.7 dB at 766 Hz, 39.0 dB at 1127 Hz, 48.9 dB at 1501 Hz, 44.5 dB at 1801 Hz. It was.
On the other hand, as shown in FIG. According to the test results of 96 specimens, the sound pressure level at the dominant frequency is 59.1 dB at 644 Hz, 40.3 dB at 766 Hz, 37.8 dB at 1127 Hz, and 38.0 dB at 1501 Hz. It was 45.1 dB at 1801 Hz.
Therefore, no. According to 96 specimens, no. It can be seen that the sound pressure level at the dominant frequency is reduced by 10.9 dB at 1501 Hz compared to 95 specimens.

Further, as shown in FIG. According to the test results of 101 specimens, the sound pressure level at the dominant frequency is 49.2 dB at 644 Hz, 39.6 dB at 766 Hz, 38.9 dB at 1127 Hz, and 43.1 dB at 1501 Hz. It was 44.5 dB at 1801 Hz.
Therefore, no. According to the test body No. 101, no. It can be seen that the sound pressure level at the dominant frequency was reduced by 7.6 dB at 644 Hz and 5.8 dB at 1501 Hz compared to the 95 specimen.

Further, as shown in FIG. According to the experimental results of 102 specimens, the sound pressure level of the dominant frequency is 54.9 dB at 644 Hz, 49.2 dB at 766 Hz, 37.0 dB at 1127 Hz, and 49.7 dB at 1501 Hz. It was 51.0 dB at 1801 Hz.
Therefore, no. According to the test body No. 102, no. It can be seen that the sound pressure level at the dominant frequency increased by 10.5 dB at 766 Hz and increased by 6.5 dB at 1801 Hz compared to 95 specimens.

In addition, as shown in FIG. According to the experimental results of 103 specimens, the sound pressure level at the dominant frequency is 52.1 dB at 644 Hz, 55.4 dB at 766 Hz, 50.3 dB at 1127 Hz, and 48.7 dB at 1501 Hz. It was 47.7 dB at 1801 Hz.
Therefore, no. According to the test body No. 103, no. Compared to 95 specimens, the sound pressure level at the dominant frequency decreased by 4.7 dB at 644 Hz, increased by 16.7 dB at 766 Hz, increased by 11.3 dB at 1127 Hz, and increased by 3.2 dB at 1801 Hz. .

  From the above results, when the width (L) of the annular surface inside the ring is 1.5 mm to 9.5 mm, the columnar tube 1 with a hole that can effectively prevent the generation of feedback oscillation sound is obtained. Further, from this result, a columnar tube with a hole that can more effectively prevent the generation of feedback oscillation sound by setting the width (L) of the annular surface inside the ring to 2.5 mm to 7.5 mm. 1 was found to be obtained.

As shown in FIG.3 (d), the difference in the effect by the difference in ring height was confirmed using each test body provided with the hole 5 one each up and down, and a total of two. 8A to 8C show the results of obtaining the A characteristic corrected sound pressure level of each specimen shown in FIG. No. The test body 60 is a columnar tube with a hole having a conventional configuration that does not include the ring protrusion 6 as shown in FIG. No. No. 119, no. The test body 120 is a columnar tube 1 with a hole according to the present invention having a ring protrusion 6 as shown in FIG.
As shown in FIG. According to the experimental results of 60 specimens, the sound pressure level at the dominant frequency is 70.1 dB at 403 Hz.
On the other hand, as shown in FIG. According to the experimental results of 119 specimens, the sound pressure level at the dominant frequency is 42.0 at 403 Hz.
Therefore, no. According to the specimen No. 119, no. In comparison with the 60 specimens, According to the experimental results of 60 specimens, it can be seen that the sound pressure level at the dominant frequency decreased by 28.1 dB at 403 Hz.

Further, No. 1 shown in FIG. According to the experimental results of 120 specimens, the sound pressure level at the dominant frequency is 39.1 dB at 403 Hz.
Therefore, no. According to the test body of No. 120, no. It can be seen that the sound pressure level at the dominant frequency was reduced by 31.0 dB at 403 Hz compared to 60 specimens.

  From the above, even if it is a columnar tube with two holes, one each for the top and bottom, a total of two holes, the ring protrusion 6 is provided and the ring width (W) of the ring protrusion 6 is 4.5 mm. The columnar tube 1 with a hole having a width (L) of the inner annular surface of 3.5 mm and a ring height (H) of 6.0 mm or 9.0 mm is at least No. It was found that the resonance in the tube 2 can be suppressed and the generated sound in the tube 2 can be reduced as compared with a columnar tube with a hole having a conventional configuration that does not include the ring protrusion 6 as in the 60 specimen. Therefore, even if it is a columnar tube with two holes, one each for the top and bottom, a total of two holes, it has a ring height (H) and a ring width (W), and an annular surface inside the ring The columnar tube 1 with a hole including a ring protrusion 6 that forms a width (L) of the hole is more effectively prevented from generating feedback oscillation sound than a columnar tube with a hole of a conventional configuration without the ring protrusion 6. It will be possible.

From the above experimental results, it was confirmed that if the ring height (H) is 4.5 mm or more and 9 mm or less, the generation of feedback oscillation sound can be more effectively prevented.
From the experimental results, the ring height (H) was determined as No. 1 in FIG. No. 90 with a performance improvement of 3.2 mm was remarkable. 3.85 mm, which is an intermediate between 91 and 4.5 mm, is estimated as the critical lower limit, and the upper limit is estimated as 10 mm as an unobtrusive height as a protrusion, and the ring height (H) is 3.85 mm or more. By setting it to 10 mm or less, it is considered that the generation of feedback oscillation sound can be more effectively prevented, and a practical columnar tube 1 with a hole can be obtained.
Also, from the experimental results, the width (L) of the annular surface inside the ring is No. 1 in FIG. No. 95, 1.5 mm, and the performance improvement was remarkable 2 mm, which is intermediate between 2.5 mm and 96, is estimated as the lower critical limit. No. 102 of 8.5 mm and performance improvement was remarkable. Estimating 8 mm, which is intermediate between 7.5 and 101 mm, as the upper critical limit, and setting the width (L) of the annular surface inside the ring to be 2 mm or more and 8 mm or less, the generation of feedback oscillation sound is more effective. It is thought that the columnar tube 1 with a hole which can be prevented can be obtained.
In the present invention, the influence of the size of the tube 2 and the size of the diameter of the hole 5 is considered to be small.

In addition, in the said form, although the pipe | tube 2 of both ends obstruction | occlusion was used, even if it comprises the columnar pipe | tube 1 with a hole which provided the ring protrusion part 6 around the hole 5 of the pipe | tube 2 of both ends open | released, an effect is acquired similarly. .
It is good also as the columnar pipe | tube 1 with a hole provided with the ring protrusion part 6 formed with the synthetic resin in the pipe | tube 2 formed with the synthetic resin.
The ring protrusion 6 may be formed in an annular shape such as a triangle or a square.

  1 columnar tube with holes, 2 tubes, 5 holes, 6 protrusions, 15 rim, 22 outer surface.

Claims (3)

Includes a section provided so as to penetrate the peripheral wall of the circular shape which is formed in the tube in and out of the tube bore, and a projecting portion of the annular surrounding the hole to protrude from the outer surface of the peripheral wall, the protruding portion, the peripheral edge of the hole It is a columnar tube with a hole provided further apart ,
The annular projecting portion is molded into a curved annular body by press-molding an annular body formed of a flat plate having a predetermined thickness with a press die having the same surface as the outer surface of the tube, The inner surface rising from the outer surface of the tube is formed by joining the curved inner surface of the toroid to the outer surface of the tube so that the center line of the circle of the torus matches the center line of the hole. A peripheral surface, an outer peripheral surface rising from the outer surface of the tube, and an annular surface connecting the rising end of the inner peripheral surface and the rising end of the outer peripheral surface;
And the columnar tube with a hole characterized by the same width | variety dimension of the annular | circular shaped surface around the hole which connects the standing | starting start edge of the internal peripheral surface of the said annular protrusion part, and the peripheral edge of the said hole .   The columnar tube with a hole according to claim 1, wherein a height of the protruding portion is set to 3.85 mm or more and 10 mm or less.   3. The columnar tube with a hole according to claim 1, wherein a distance between the rising start edge of the inner peripheral surface of the projecting portion and the peripheral edge of the hole is 2 mm or more and 8 mm or less.

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