JP4677219B2 - Bent duct - Google Patents

Description

  The present invention relates to a bent duct, and more specifically, includes a first duct portion and a second duct portion which is bent substantially at right angles and is connected to the first duct portion, and fluid such as air flowing into the first duct portion. The present invention relates to a bent duct that is blown out from the rear end opening of the second duct portion.

  In order to distribute and guide various fluids such as air, various forms (shapes, sizes, etc.) of ducts have been proposed and put into practice. For example, FIG. 12 is a perspective view partially illustrating a bent duct Do disposed inside an instrument panel or the like that is a vehicle interior member. The bent duct Do is bent substantially at a right angle and connected to the first duct portion 10. The second duct portion 20 is provided. That is, the bent duct Do has a front end opening 12 of the first duct portion 10 connected to an air conditioner unit (not shown) and a rear end opening 22 of the second duct portion 20 connected to an air outlet (not shown). From the rear end opening 22 of the second duct portion 20, the air flowing into the first duct portion 10 is blown out (sent out).

By the way, in the bending duct Do mentioned above, from the restriction | limiting of the internal structure of an instrument panel, etc., the 1st duct part 10 and the 2nd duct part 20 are connected in a substantially right angle, and the shape by which the bending part bent rapidly In many cases. For this reason, when the amount of air per unit time flowing through the duct increases and the flow velocity increases, the air flow and turning at the bent portion described above do not become smooth, and the second duct portion 20 The problem is that the flow air is separated at the inner part (inner corner side part) and is biased toward the outer side, resulting in uneven air blowing at the rear end opening 22 and increased pressure loss. Will occur. Therefore, a configuration (illustrated in FIG. 14) in which the curvature radius of the bent portion between the first duct portion 10 and the second duct portion 20 is increased, or a rectifying plate for smoothly changing the direction of the circulating air inside the bent portion. A form of providing 14 (illustrated in FIG. 15) and the like have been proposed. A technique related to such a bent duct is disclosed in, for example, Patent Document 1 and the like.
Japanese Utility Model Publication No. 6-85905

  Incidentally, in the bent duct Do illustrated in FIG. 14, when the extension length L of the second duct portion 20 is defined, if the curvature radius of the bent portion is increased, the straight portion of the second duct portion 20 is almost eliminated. In addition, there is a problem that the blowing direction of the air blown from the rear end opening 22 is biased obliquely forward, and the air does not blow out in front of the rear end opening 22 on the average. On the other hand, the bent duct Do illustrated in FIG. 15 has a problem in that the internal cross-sectional area of the bent portion is reduced by the thickness of the rectifying plate 14 and the flow resistance is likely to increase accordingly. In particular, in the case of a bent duct formed based on the blow molding technique, the width of formation of the rectifying plate 14 is inevitably widened, the reduction rate of the internal cross-sectional area is increased, and the flow resistance is increased. It will manifest further.

  Accordingly, an object of the present invention is to provide a bent duct that can average (homogenize) the blow-out of air from the rear end opening.

In order to solve the above-mentioned problems and achieve the intended purpose, the present invention provides:
A first duct portion and a second duct portion connected to the first duct portion so as to be bent at a substantially right angle, and the air flowing into the first duct portion is blown out from the rear end opening of the second duct portion. In the bending duct,
The first duct portion and the second duct portion are connected to the outer wall portion of the first duct portion and the outer wall portion of the second duct portion on the inner corner side of the bent portion of the first duct portion and the second duct portion, respectively. With a bypass to communicate with each other spatially,
The bypass passage, while the inlet angle are connected by 4 5 to 60 ° with respect to the outer wall of the first duct portion, connected at the outlet angle of 45 to 30 ° with respect to the outer wall of the second duct portion And
The bypass passage has a width along the inner angle of the bent portion on the first duct portion side set to be equal to the entire width of the first duct portion, and a width along the inner angle of the bent portion on the second duct portion side. Set equal to the full width of the second duct portion;
The bypass passage has an internal cross-sectional area in the direction orthogonal to the air flow direction set to 1/5 to 1/2 times the internal cross-sectional area in the direction orthogonal to the air flow direction of the first duct portion ,
The connection position between the bypass passage and the first duct portion is such that the distance from the inner angle of the bent portion to the bypass passage is in the direction along the air flow direction of the first duct portion in the second duct portion. It is characterized by being set smaller than the width .

  According to the bent duct according to the present invention, the first duct portion and the second duct portion are spatially arranged on the inner angle side of the bent portion between the first duct portion and the second duct portion that are arranged substantially at right angles. By providing a bypass path that communicates, and a part of the air in the first duct portion flows out into the second duct portion through the bypass path, air from the rear end opening of the second duct portion, etc. There is a beneficial effect that the discharge of the fluid can be averaged. Further, since the bypass path functions as a so-called reinforcing rib, the rigidity of the entire duct is improved, and there is an advantage that bending deformation in the bending direction can be suitably prevented.

  Next, the bent duct according to the present invention will be described below with reference to the accompanying drawings by way of preferred embodiments. In the embodiment described later, the basic shape is the same as that of the conventional bent duct Do illustrated in FIG. 12, and the same members and portions as those of the bent duct Do will be described with the same reference numerals.

  FIG. 1 is a perspective view showing a schematic shape of a bent duct according to a preferred embodiment, and FIG. 2 is a cross-sectional view taken along line II-II in FIG. The bent duct Dn according to the present embodiment includes a first duct portion 10 and a second duct portion 20 that is bent substantially at a right angle and is connected to the first duct portion 10. The air flowing into the portion 10 is blown out from the rear end opening 22 of the second duct portion 20. Here, the “substantially right angle” defined by the present application includes not only a right angle that is correctly 90 ° but also an angle slightly smaller than the right angle (for example, about 80 °) to an angle slightly larger than the right angle (about 100 °). . In addition, the thickness of the 1st duct part 10 and the 2nd duct part 20 is the same, Both internal cross-sectional areas (cross-sectional area of the direction which cross | intersects a distribution direction) W1 and W2 are also the same.

  The bent duct Dn of the present embodiment has an outer wall portion of the first duct portion 10 on the inner angle side (narrow angle side) of the bent portion that is a continuous portion of the first duct portion 10 and the second duct portion 20. A bypass path 30 that spatially communicates with the outer wall portion of the second duct portion 20 is provided. As a result, a part of the air that has flowed into the first duct portion 10 described above is allowed to flow out into the second duct portion 20 via the bypass passage 30 without passing through the bent portion as the diverted air, and the rear end opening 22. The air blow-out from can be averaged. That is, the mainstream air that has flowed from the first duct portion 10 into the second duct portion 20 via the bent portion tends to circulate in an outward direction of the second duct portion 20, and thus has passed through the bypass passage 30. The air is blown out from the entire area of the rear end opening 22 by causing the diverted air to flow out inward of the second duct portion 20 (the outlet wind speed is made uniform).

  Here, as illustrated in FIG. 1, the bypass path 30 has an inner angle side in the first duct portion 10 at a position separated by a predetermined distance S from the inner angle end 32 of the bent portion to the upstream side of the first duct portion 10. One end side is connected to the directed outer wall portion 16, and the other end side is connected to the outer wall portion 26 directed to the inner corner side in the second duct portion 20. And, it is connected to the first duct portion 10 at the inlet angle R1, and is connected to the second duct portion 20 at the outlet angle R2, from the first duct portion 10 toward the second duct portion 20. It is provided diagonally and linearly.

  Further, the internal cross-sectional area (cross-sectional area in the direction crossing the flow direction) W3 of the bypass passage 30 is set in a range of 1/5 to 1/2 times the internal cross-sectional area W1 of the first duct portion 10. Further, the width M of the bypass passage 30 is substantially equal to the full width N1 of the first duct portion 10 on the first duct portion 10 side, and the full width N2 of the second duct portion 20 on the second duct portion 20 side. It is almost equivalent. Accordingly, in the bent duct Dn of the present embodiment, the entire width N1 of the first duct portion 10 and the entire width 20 of the second duct portion 20 are the same, so the width M of the bypass passage 30 is constant. The “equivalent” defined here includes the case where the width M of the bypass path 30 is slightly smaller, as well as the same.

  The inlet angle R1 described above is the angle of the bent portion, the internal cross-sectional area W1 of the first duct portion 10, the internal cross-sectional area W3 of the bypass passage 30, the width M of the bypass passage 30, and the first duct 12 via the tip opening 12. It is determined on the premise of various conditions such as a flow rate of air flowing into the portion 10 per unit time. Specifically, based on the results of experiments conducted by the inventors of the present application (described later), the entrance angle R1 is set in the range of 40 to 60 °, and more preferably about 45 to 60 °.

  Further, the outlet angle R2 described above is determined by the inner angle of the bent portion and the inlet angle R1 when the bypass passage 30 is provided in a straight line. If the angle of the bent portion is a right angle (90 °), then the outlet angle R2 is necessarily R2. = 90-R1. Accordingly, the outlet angle R2 is 50 ° when the inlet angle R1 is 40 °, and 30 ° when the inlet angle R1 is 60 °, and the outlet angle R2 is set in the range of 50 to 30 °.

  In addition, the bending duct Dn of the present embodiment provided with the above-described bypass passage 30 is integrally molded from a resin material such as polyethylene or polypropylene based on a blow molding technique, or from the above-described resin material to an injection molding technique. It is possible to form a plurality of pieces formed based on the above. Since the bypass duct 30 functions as a so-called reinforcing rib in any of the molded ducts Dn, the rigidity of the entire duct is improved and the flexural deformation in the bending direction is achieved. Can be suitably prevented. Moreover, the duct main body which consists of the 1st duct part 10 and the 2nd duct part 20, and the bypass path 30 may be shape | molded separately, respectively, and you may make it assemble this bypass path 30 with respect to a duct main body in a post process. .

(Experimental example)
Table 1 and FIGS. 3 to 10 show experiments conducted by the inventor of the present application in order to obtain an appropriate arrangement mode (arrangement angle) of the bypass passage 30 with respect to the bent duct Dn of the present embodiment provided with the bypass passage 30. The results are shown. Here, this experiment is based on the premise that the bent duct Dn is used for the purpose of guiding temperature-controlled air sent from an air conditioner unit (not shown) to the air outlet, which is disposed inside the instrument panel or the like. The experimental conditions were set to be close to the actual usage environment. Each experimental condition is as follows.

(a) Various dimensions of the first duct portion 10-Internal width E1: 70 mm
・ Internal height F1: 70mm
Internal cross-sectional area W1: 4900mm ² (70mm x 70mm)
(b) Dimensions of second duct portion 20-Internal width E2: 70 mm
・ Internal height F2: 70mm
(c) Bending angle: 90 ° (right angle)
(d) Distance S from the inner corner end of the bent portion: 25 mm
(e) Various dimensions of bypass path 30-Internal cross-sectional area W3: 1750 mm ² (25 mm x 70 mm)
(= About 1/3 of the internal sectional area W1 of the first duct portion 10)
Width M: 72 mm (= full width N1 of the first duct portion 10 = full width N2 of the second duct portion 20)
(f) Air flow rate: 2 m ³ / min

  The experimental contents are a total of six types of bending ducts Dn1 to Dn6 in which the inlet angle R1 and the outlet angle R2 of the bypass passage 30 are changed under the above-described experimental conditions, and the inner angle of the bent portion without providing the bypass passage 30. With respect to the two types of bent ducts Dn7 and Dn8 having the inclined surface 40 and the curved surface 42 as surfaces, the maximum outlet wind velocity Vmax and the pressure loss at the rear end opening 22 are measured. As an evaluation determination, the numerical values of the maximum outlet wind speed Vmax and the pressure loss Po measured at the rear end opening 22 are larger than the maximum outlet wind speed Vmax and the pressure loss Po of the conventional bent duct Do illustrated in FIGS. I decided to make it smaller.

Further, when the opening area of the rear end opening 22 of the second duct portion 20 is 4900 mm ² and the air flow rate is 2 m ³ / min, the theoretical average outlet wind speed is 6.80 m / s. It can be determined that the portion where the numerical value of the maximum outlet wind speed Vmax is larger than the average flow velocity is that air is intensively blown out. As the numerical value of the outlet maximum wind speed Vmax is larger, the bias of the air blowing from the rear end opening 22 is larger (air is intensively blown), and the bypass passage 30 functions effectively. Means no. In other words, the air blowing from the rear end opening 22 is averaged as the maximum outlet wind speed Vmax is closer to the average outlet flow velocity.

  First, in the case of the bent duct Dn1 with the inlet angle R1 = 35 ° and the outlet angle R2 = 55 °, as exemplified in Table 1 and FIG. 3, the outlet maximum wind speed Vmax = 8.79 m / s, the pressure loss Po = The values were 15.9 Pa, and the respective values were substantially the same as the values of the conventional bent duct Do illustrated in FIG. 13 (Vmax = 8.71 m / s, Po = 15.3 Pa). Moreover, as is clear from FIG. 3, the diverted air that has entered the bypass passage 30 flows out of the second duct portion 20 toward the outside and vigorously flows into the second duct portion 20 via the bent portion. Have joined. Therefore, it can be seen that the separation phenomenon of the circulating air still occurs in the inner portion (inner corner side portion) of the second duct portion 20, and the air from the rear end opening 22 is not blown out on average (uniformly). This is because the inlet angle R1 of the bypass passage 30 with respect to the first duct portion 10 is too small, so that air easily enters the bypass passage 30 and there is too much inflow of the shunt air, and it is not reduced. This is presumed to be due to the vigorous outflow into the second duct portion 20. Moreover, since the exit angle R <b> 2 with respect to the second duct portion 20 is too large, it is considered that the diverted air is difficult to flow out inward of the second duct portion 20. That is, when the inlet angle R1 of the bypass path 30 is set to 35 ° or less, the effect of providing the bypass path 30 is hardly expressed, and it is evaluated that the effect of providing the bypass path 30 is low. .

  In the case of the bent duct Dn2 with the inlet angle R1 = 40 ° and the outlet angle R2 = 50 °, as exemplified in Table 1 and FIG. 4, the outlet maximum wind speed Vmax = 8.60 m / s, the pressure loss Po = 14. 2 Pa, which is better than the values of the conventional bent duct Do illustrated in FIG. 13 (Vmax = 8.71 m / s, Po = 15.3 Pa), and the effect of providing the bypass 30 is exhibited. However, as is apparent from FIG. 4, the separation phenomenon of the circulating air still occurs in the inner portion of the second duct portion 20, and there is still some dissatisfaction in that air is blown out from the rear end opening 22 on the average. Evaluated to remain.

  In the case of the bent duct Dn3 in which the inlet angle R1 = 45 ° and the outlet angle R2 = 45 °, as illustrated in Table 1 and FIG. 5, the outlet maximum wind speed Vmax = 8.52 m / s, the pressure loss Po = 13. 6 Pa, which is considerably better than the values of the conventional bent duct Do illustrated in FIG. 13 (Vmax = 8.71 m / s, Po = 15.3 Pa). In addition, the result is better than the case of the inlet angle R1 = 40 ° and the outlet angle R2 = 50 °, and the effect of providing the bypass path 30 is suitably expressed. Further, as apparent from FIG. 5, the diverted air from the bypass passage 30 flows out toward the inner side of the second duct part 20, and almost no separation phenomenon of the circulating air occurs in the inner part of the second duct part 20. It can be evaluated that air is blowing out from the rear end opening 22 on the average.

  In the case of the bent duct Dn4 in which the inlet angle R1 = 50 ° and the outlet angle R2 = 40 °, as illustrated in Table 1 and FIG. 6, the outlet maximum wind speed Vmax = 8.50 m / s, and the pressure loss Po = 13. Of course, the value is 5 Pa, in addition to the values of the conventional bent duct Do illustrated in FIG. 13 (Vmax = 8.71 m / s, Po = 15.3 Pa), as compared with the case where the inlet angle R1 = 45 ° and the outlet angle R2 = 45 °. Even in this case, the effect of providing the bypass path 30 is favorably expressed. Further, as is clear from FIG. 6, the diverted air from the bypass passage 30 flows out toward the inner side of the second duct part 20, and the separation phenomenon of the circulating air occurs at the inner part of the second duct part 20. However, judging from the numerical values described above, it can be evaluated that air is blown out uniformly from the rear end opening 22.

  In the case of the bent duct Dn5 in which the inlet angle R1 = 60 ° and the outlet angle R2 = 30 °, as illustrated in Table 1 and FIG. 7, the outlet maximum wind speed Vmax = 8.58 m / s, the pressure loss Po = 14. 7 Pa, which is better than the values of the conventional bent duct Do illustrated in FIG. 13 (Vmax = 8.71 m / s, Po = 15.3 Pa), and the effect of providing the bypass 30 is exhibited. However, the effect is slightly reduced as compared with the case where the inlet angle R1 = 50 ° and the outlet angle R2 = 40 °, or the case where the inlet angle R1 = 45 ° and the outlet angle R2 = 45 °. As is clear from FIG. 7, the air separation phenomenon starts to occur again in the inner portion of the second duct portion 20. However, judging from the numerical values described above, it can be evaluated that air is blown out relatively uniformly from the rear end opening 22.

  In the case of the bent duct Dn6 with the inlet angle R1 = 70 ° and the outlet angle R2 = 20 °, as illustrated in Table 1 and FIG. 8, the outlet maximum wind speed Vmax = 8.70 m / s, the pressure loss Po = 17.3 Pa, which is worse than the values of the conventional bent duct Do illustrated in FIG. 13 (Vmax = 8.71 m / s, Po = 15.3 Pa). As apparent from FIG. 8, the inlet angle R <b> 1 of the bypass passage 30 is too large and it becomes difficult for air to enter the bypass passage 30, and the air flows into the second duct portion 20 through the bypass passage 30. This is presumed to be due to the minute amount of shunting air. Therefore, most of the air becomes mainstream air and concentrates and flows out to the outer side of the second duct portion 20, and the inner portion of the second duct portion 20 has the flow air flowing in the same manner as the conventional bent duct Do. A peeling phenomenon occurs, and air does not blow out from the rear end opening 22 on the average. That is, when the inlet angle R1 of the bypass passage 30 is set to 70 ° or more, the effect of providing the bypass passage 30 hardly appears, but rather the pressure loss Po is increased by providing the bypass passage 30. It has been found that it has an adverse effect.

  On the other hand, in the case of the bent duct Dn7 in which the above-described bypass passage 30 is not provided and the inclined surface 40 of about 45 ° is formed at the inner corner of the bent portion, as illustrated in Table 1 and FIG. = 8.54 m / s and pressure loss Po = 14.5 Pa, which is an improvement over the values of the conventional bent duct Dn illustrated in FIG. 13 (Vmax = 8.71 m / s, Po = 15.3 Pa). The uniformity of the blowout is getting worse. As is apparent from FIG. 9, separation of the circulating air occurs at the boundary edge portion between the wall surface of the first duct portion 10 and the inclined surface 40, and the air flows along the inclined surface 40. This is because air flows out from the second duct portion 20 in a concentrated manner in the same manner as the conventional bent duct Do illustrated in FIG. Therefore, the separation phenomenon of the circulating air still occurs in the inner portion of the second duct portion 20, and air is not blown out from the rear end opening 22 on the average. That is, it can be evaluated that the effect of providing the inclined surface 40 on the inner corner side of the bent portion is hardly expressed, and that it is not possible to realize an average blowing of air.

  Further, in the case of the bent duct Dn8 in which the above-described bypass passage 30 is not provided and the curved surface 42 having a relatively large radius of curvature is formed at the inner corner of the bent portion, as shown in Table 1 and FIG. Vmax = 8.37 m / s and pressure loss Po = 11.3 Pa, and compared with the values of the conventional bent duct Do illustrated in FIG. 13 (Vmax = 8.71 m / s, Po = 15.3 Pa), the outlet The maximum wind speed Vmax is reduced and the pressure loss Po is reduced. As apparent from FIG. 10, since the flowing air flows along the curved surface 42, the air also blows out from the inner side direction of the second duct portion 20, and thus from the rear end opening 22. It is estimated that air blows out relatively on average. However, since the air diffusion immediately after being blown out from the rear end opening 22 becomes considerably large and further tends to be deflected obliquely forward, the air is blown out. Therefore, the same problem as that of the bent duct Do illustrated in FIG. It is expressed.

  Therefore, even if the inclined surface 40 or the curved surface 42 is formed on the inner corner side of the bent portion and the internal cross-sectional area of the bent portion is increased, the outflow of air from the rear end opening 22 is preferably averaged. In addition, it was found that reduction of pressure loss could not be expected much. And it became clear once again that it is effective, effective and effective in order to average the blowing of the air from the rear end opening 22 to appropriately provide the bypass passage 30 on the inner corner side of the bent portion.

  From the above experimental results, in the case of the bent duct Dn that is disposed on the back side of the vehicle interior member such as an instrument panel and is used for air conditioning in the passenger compartment, the arrangement of the bypass passage 30 described above is used. It has been found that it is desirable to set the installation mode in the range of the inlet angle R1 = 40 to 60 ° and in the range of the outlet angle R2 = 50 to 30 °. It has also been found that, if the inlet angle R1 is set to about 45 to 60 °, a further improvement in effect can be expected.

  As described above, in the bent duct Dn of the present embodiment, the first duct portion 10 and the second duct portion 20 are disposed on the inner angle side of the bent portion between the first duct portion 10 and the second duct portion 20 that are connected substantially at right angles. Since a part of the air in the first duct portion 10 flows out into the second duct portion 20 through the bypass passage 30 by providing the bypass passage 30 that spatially communicates with the second duct portion 10, the second The blowout of air from the rear end opening 22 of the duct portion 20 can be averaged. And it becomes possible to express the effect suitably by setting entrance angle R1 provided in a row by the 1st duct part 10 to 40-60 degrees.

  FIG. 11A is a schematic cross-sectional view of a bent duct Dn according to a modified example in which the form of the bypass path 30 is changed. In the bending duct Dn of the above-described embodiment, the case where the bypass passage 30 is provided linearly from the first duct portion 10 to the second duct portion 20 is illustrated. However, in the bending duct Dn of this modified example, the bypass passage is provided. 30 is provided in a curved shape from the first duct portion 10 toward the second duct portion 20. When the bypass passage 30 has such a configuration, it becomes easy for a fluid such as air to enter the bypass passage 30 from the first duct portion 10, and the fluid that has been divided flows from the bypass passage 30 to the second passage. It becomes easy to flow out along the inner side direction of the duct part 20.

  FIG. 11B is a schematic cross-sectional view of a bent duct Dn according to another modified example in which the form of the bypass passage 30 is further modified. In the bent duct Dn of this other modified example, the bypass passage 30 is configured by a curved portion 44 connected to the first duct portion 10 and a straight portion 46 connected to the second duct portion 20. . When the bypass passage 30 has such a configuration, it is easy for a fluid such as air to enter the bypass passage 30 from the first duct portion 10 and the diverted fluid to the second duct portion 20 at a required angle. Can be drained smoothly. Although not shown, the side connected to the first duct portion 10 may be a straight portion and the side connected to the second duct portion 20 may be a curved portion.

  In the above-described embodiment, the bent duct installed in the vehicle passenger compartment is illustrated, but the bent duct targeted by the present application is not limited to this, and is implemented in various fields such as various blowers and fluid machinery. All ducts that are made are targeted. Further, the fluid to be guided to flow is not limited to air, and a duct for circulating and guiding various gases other than air, various liquids typified by oil or water, and the like is targeted.

  The bent duct according to the present invention includes a first duct portion and a second duct portion that is bent substantially at a right angle and is connected to the first duct portion, and fluid such as air flowing into the first duct portion is supplied to the second duct. All bent ducts that are delivered from the rear end opening of the portion and that guide the flow of various gases or liquids are all targeted.

1 is a schematic perspective view of a bent duct according to a preferred embodiment. It is the II-II sectional view taken on the line of FIG. It is explanatory sectional drawing which illustrated the air blowing aspect of the bending duct which made the entrance angle of the bypass path 35 degrees, and the exit angle 55 degrees. It is explanatory sectional drawing which showed the air blowing aspect of the bending duct which made the entrance angle of the bypass channel 40 degrees, and made the exit angle 50 degrees. It is explanatory sectional drawing which showed the air blowing aspect of the bending duct which made the entrance angle of the bypass path 45 degrees, and the exit angle 45 degrees. It is explanatory sectional drawing which showed the air blowing aspect of the bending duct which made the entrance angle of the bypass path 50 degrees, and the exit angle 40 degrees. It is explanatory sectional drawing which showed the air blowing aspect of the bending duct which made the entrance angle of the bypass path 60 degrees, and the exit angle 30 degrees. It is explanatory sectional drawing which showed the air blowing aspect of the bending duct which made the entrance angle of the bypass path 70 degrees, and the exit angle 20 degrees. It is explanatory drawing which showed the air blowing aspect of the bending duct which did not provide a bypass path and made the internal angle side of the bending part into the slanting surface. It is explanatory drawing which showed the air blowing aspect of the bending duct which did not provide a bypass path and made the internal angle side of the bending part the curved surface. It is explanatory sectional drawing of the bending duct which concerns on a modification, Comprising: (a) illustrated the form which made the bypass path curved, (b) formed the bypass path from the curved part and the linear part. Illustrated. It is the schematic perspective view which illustrated the conventional bending duct. It is explanatory sectional drawing which showed the air blowing aspect of the bending duct illustrated in FIG. It is explanatory sectional drawing which showed the air blowing aspect of the bending duct which enlarged the curvature radius of the bending part. It is explanatory sectional drawing which showed the air blowing aspect of the bending duct which provided the baffle plate inside the bending part.

Explanation of symbols

10 First duct part
16 Outer wall portion 20 Second duct portion 22 Rear end opening
26 Outer wall 30 Bypass road
32 Inner corner edge
44 Curved part
46 Straight line
E2 Internal width N1 Full width (of the first duct part 10)
N2 full width (second duct part 20)
M width (bypass path 30)
R1 inlet angle R2 outlet angle
S Distance W1 Internal sectional area (of the first duct portion 10)
W3 Internal cross-sectional area (bypass path 30)

Claims (4)

The first duct part (10) and the second duct part (20) bent and connected to the first duct part (10) at a substantially right angle and connected to the first duct part (10), the air flowing into the first duct part (10) In a bent duct that blows out the rear end opening (22) of the second duct part (20),
An outer wall portion (16) of the first duct portion (10) and an outer wall portion (2) of the second duct portion (20) are disposed on the inner corner side of the bent portion of the first duct portion (10) and the second duct portion (20). 26) each having a bypass passage (30) connected spatially between the first duct portion (10) and the second duct portion (20),
Said bypass passage (30), the first one of the inlet angle to the outer wall of the duct section (10) (16) (R1) is connected in 4 5 to 60 °, the second duct portion (20) The outlet angle (R2) is connected to the outer wall portion (26) at 45 to 30 °,
The bypass passage (30) has a width along the inner angle of the bent portion on the first duct portion (10) side that is set equal to the entire width (N1) of the first duct portion (10), and the second duct. The width along the inner angle of the bent portion on the side of the portion (20) is set equal to the total width (N2) of the second duct portion (20),
The bypass passage (30) has an internal cross-sectional area (W3) in the direction orthogonal to the air flow direction, which is 1 of the internal cross-sectional area (W1) in the direction orthogonal to the air flow direction of the first duct portion (10). Set to / 5 to 1/2 times ,
The connection position between the bypass passage (30) and the first duct portion (10) is such that the distance (S) from the inner angle of the bent portion to the bypass passage (30) is the second duct portion (20). The bent duct characterized by being set smaller than the internal width (E2) in the direction along the air flow direction of the first duct portion (10) . The bent duct according to claim 1 , wherein the bypass passage (30) is provided linearly from the first duct portion (10) to the second duct portion (20). It said bypass passage (30), the first duct portion (10) towards the second duct portion (20), bending duct provided in which claim 1 Symbol placement in a curved shape protruding into the bent portion . It said bypass passage (30), bending of the first duct portion (10) side of the curved portion (44) and the second duct portion (20) side of the straight portion (46) claims 1 Symbol placement consists duct.

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