JP2007326448A - Duct for air conditioning - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a duct for air conditioning capable of reducing noise generated in an air conditioner for a vehicle. <P>SOLUTION: A curved part arranged on the air conditioner for the vehicle and having a center shaft formed into a curved shape, a straightening part continuous to an air flow passage downstream side of the curved part to have a center shaft formed into a straight line and radial direction cross section of a fixed shape, a throttle part continuous to an air flow passage downstream side of the straightening part to reduce radial direction cross sectional area toward the air flow passage downstream side, and a return part continuous to the air flow passage downstream side of the throttle part to gradually increase the radial direction cross sectional area toward the air flow passage downstream side are provided on an internal surface of this duct. The air flow passage downstream side part of the throttle part is made smoothly continuous to the return part. Radial direction cross sectional area S1 of an air flow passage downstream side end part of the throttle part is made ≥9/20 of radial direction cross sectional area S2 of the straightening part. An axial direction length of the throttle part is made ≤1/4 of a radius of a circle having area equal to S2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an air conditioning duct that is connected to a downstream side of an air flow path of a vehicle air conditioner and guides air that has flowed out of the vehicle air conditioner in a predetermined direction.

  The air conditioning duct connected to the vehicle air conditioner (so-called air conditioner) has a cylindrical shape. The air blown out from the vehicle air conditioner flows through the air conditioning duct. That is, the inside of the air conditioning duct becomes an air flow path. Some air conditioning ducts can adjust the flow rate of air in the air flow path (see, for example, Patent Document 1).

  The air conditioning duct introduced in Patent Document 1 has a pair of blades. The wing plate is elastically deformable and is disposed in the air flow path. If the vane plate is curved, the air flow path is narrowed, so that the air flow rate in the air flow path is reduced.

  However, in this type of air conditioning duct, noise (wind noise) may occur in the vicinity of the blade depending on the shape of the curved blade. In order to reduce this noise, in the air conditioning duct of Patent Document 1, the blades are bent symmetrically. If the blades are symmetrically curved, the conditioned air flows smoothly even in the vicinity of the blades, so that the generation of noise can be suppressed.

By the way, the vehicle air conditioner to which the air conditioning duct is connected not only serves as a supply source of air but also serves as a noise source. For this reason, in recent years, an air-conditioning duct that can reduce noise derived from a vehicle air-conditioning apparatus is desired. As introduced in Patent Document 1, a technique for reducing noise generated when an air flow path is narrowed has been proposed. However, no study has been made on the technology for reducing the noise derived from the vehicle air conditioner.
JP-A-8-42913

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an air conditioning duct that can reduce noise generated in a vehicle air conditioner.

  The air-conditioning duct of the present invention that solves the above problems is an air-conditioning duct that has a cylindrical shape and is connected to the downstream side of the air flow path of the vehicle air-conditioning apparatus. A curved portion having a curved central axis, a rectifying portion that is continuous with the downstream side of the air flow path of the curved portion, has a straight central axis, and has a constant radial cross section, and air in the rectifying portion A throttle part that is continuous to the downstream side of the flow path and has a radial cross-sectional area that decreases toward the downstream side of the air flow path, and a radial cross-sectional area that is continuous to the downstream side of the air flow path of the throttle part A gradually increasing return portion, the air flow path downstream side portion of the throttle portion is smoothly continuous with the return portion, and the radial cross-sectional area S1 of the air flow path downstream end portion of the throttle portion is the diameter of the rectifying portion. 9/20 or more of the directional cross-sectional area S2, and the axial length of the throttle portion is the radius of a circle whose area is equal to S2. Characterized in that it is 1/4 or less.

The air conditioning duct according to the present invention preferably includes any of the following (1) to (3). It is desirable to provide a plurality of (1) to (3).
(1) Said S1 is 9/16 or more of said S2.
(2) The axial length of the rectifying unit is 30 mm or more.
(3) The angle formed by the central axis L1 of the rectification unit and the straight line L2 that is on the same plane as L1 and passes through the downstream end of the air flow path of the return unit and contacts the return unit is 5 ° or less. is there.

  The air-conditioning duct of the present invention has a throttle portion. The radial cross-sectional area of the throttle portion decreases toward the downstream side of the air flow path. Therefore, noise generated in the vehicle air conditioner and transmitted through the air flow path is attenuated by the throttle portion. For this reason, the air-conditioning duct of the present invention can reduce noise generated in the vehicle air-conditioning apparatus.

  Incidentally, since the radial cross-sectional area of the throttle portion is small, the air conditioning duct of the present invention has an increased air pressure loss (hereinafter abbreviated as pressure loss) as compared with an air conditioning duct having no throttle portion.

  In view of this point, in the air conditioning duct according to the present invention, the downstream portion of the throttle portion in the air flow path (that is, the portion on the return portion side) is smoothly continuous with the return portion. In the air-conditioning duct according to the present invention, the downstream portion of the throttle portion in the air flow path smoothly continues to the return portion, so that the air that has passed through the throttle portion smoothly flows into the return portion. Therefore, the air conditioning duct of the present invention can suppress an increase in pressure loss.

  Moreover, the radial cross-sectional area of the return portion gradually increases toward the downstream side of the air flow path. For this reason, the air which flowed into the return part flows smoothly through the return part. The air conditioning duct of the present invention can also suppress an increase in pressure loss due to this.

  Further, the radial cross-sectional area S1 of the downstream end portion of the air flow path of the throttle portion is 9/20 or more of the radial cross-sectional area S2 of the rectifying portion. For this reason, in the air-conditioning duct of the present invention, the radial cross-sectional area of the throttle portion does not become excessively small. The air conditioning duct of the present invention can also suppress an increase in pressure loss due to this.

  By the way, the longer the axial length of the throttle portion, the more noise caused by the vehicle air conditioner can be reduced. However, the longer the axial length of the throttle portion, the greater the pressure loss. Therefore, in order to suppress an increase in pressure loss while reducing noise caused by the vehicle air conditioner, it is necessary to set the axial length of the throttle portion to a predetermined length or less. In the air conditioning duct of the present invention, the axial length of the throttle portion is not more than ¼ of the radius of a circle whose area is equal to S2 (hereinafter referred to as r2), and is sufficiently short. Therefore, according to the air conditioning duct of the present invention, an increase in pressure loss can be reliably suppressed.

  The air conditioning duct of the present invention is connected to a vehicle air conditioner and is mounted on a vehicle. The air flow path upstream end of the air conditioning duct is connected to the vehicle air conditioner. The downstream end of the air channel is generally connected to a blowing member such as an air conditioning register or a defroster. The vehicle air conditioner and the blowing member are generally not arranged linearly. Therefore, a portion (curved portion) in which the central axis forms a curved shape is formed in the air conditioning duct connected thereto. By the way, in the case where the throttle portion continues to the downstream side of the air flow path of the curved portion, the air flowing through the curved portion, that is, the air flowing while being curved flows directly into the throttle portion. Therefore, the pressure loss at the throttle portion increases. In the air-conditioning duct according to the present invention, a rectifying unit is provided between the curved portion and the throttle unit, and the air flowing into the throttle unit is arranged in advance, so that the air that has passed through the rectifying unit is smooth in the throttle unit. Flow into. Therefore, an increase in pressure loss at the throttle portion can be suppressed.

  The air conditioning duct of the present invention having the above (1) has the advantages that noise caused by the vehicle air conditioner can be sufficiently reduced and an increase in pressure loss can be more reliably suppressed.

  The air conditioning duct of the present invention having the above (2) has a long axial length of the rectifying unit. For this reason, the air which passed the rectification | straightening part flows in more smoothly by a throttle part. Therefore, an increase in pressure loss at the throttle portion can be more reliably suppressed.

  In the air conditioning duct of the present invention having the above (3), the angle formed by L1 and L2 is 5 ° or less, and therefore the radial section of the return portion does not suddenly increase. Therefore, according to the air conditioning duct of the present invention having the above (3), an increase in pressure loss can be more reliably suppressed.

  The air-conditioning duct of the present invention only needs to be cylindrical, and the shape thereof may be any shape such as cylindrical or rectangular tube. The wall thickness of the air conditioning duct of the present invention may be constant or not constant. That is, the inner shape and the outer shape of the air conditioning duct of the present invention may be the same shape or different shapes.

  The return portion may be directly connected to the blowing member described above or may be indirectly connected. For example, a second curved part may be provided on the downstream side of the air flow path of the return part, and the second curved part may be connected to the blowing member. Similarly, the bending portion may be directly connected to the vehicle air conditioner or may be indirectly connected.

  The throttle part and the return part may be formed so that the central axis is curved, but it is better to form the central axis so as to be linear. If the throttle part and the return part are formed so that the central axis is linear, an increase in pressure loss can be more reliably suppressed.

  The portion of the throttle portion downstream of the air flow path smoothly continues to the return portion. For this reason, a portion where the radial cross-sectional area gradually decreases (hereinafter, referred to as a gradual gradual change portion) is generated in at least a portion of the throttle portion in the axial direction. The restricting portion may be constituted only by the restricting gradually changing portion, but in this case, the axial length of the restricting portion becomes excessive, and the pressure loss may increase. By providing a portion (hereinafter referred to as a sudden change in diameter) where the radial cross-sectional area is abruptly reduced in a portion of the throttle portion in the axial direction, the axial length of the throttle portion is not excessive, and pressure loss The increase can be reliably suppressed. In this case, in order to surely suppress an increase in pressure loss, it is preferable that the rapid diaphragm change portion and the throttle gradual change portion continue smoothly. For example, if the line segment obtained by cutting the aperture portion in the axial direction is formed in an arc shape, the aperture suddenly changing portion and the aperture gradually changing portion are smoothly continuous.

  As described above, in the air conditioning duct of the present invention, the axial length of the throttle portion is ¼ or less of r2. In order to reduce noise caused by the vehicle air conditioner while reliably suppressing an increase in pressure loss, it is preferable to set the axial length of the throttle portion to a predetermined length or more. In the air conditioning duct according to the present invention, it is preferable that the axial length of the throttle portion is 10 mm or more. If the axial length of the throttle portion is 10 mm or more, noise caused by the vehicle air conditioner can be reliably reduced.

  In the air-conditioning duct of the present invention, in order to more reliably suppress an increase in pressure loss, the radial cross-sectional area of the rectifying unit and the radial cross-sectional area of the downstream end of the air flow path of the return unit are the same. Preferably there is. This is to reliably suppress an increase in pressure loss on the downstream side of the air flow path from the return portion in the air conditioning duct.

  In the air conditioning duct according to the present invention, the central axis of the rectifying unit and the central axes of the throttle unit and the return unit may or may not coincide with each other. In other words, the radial cross section of the downstream end portion of the air flow path of the throttle portion may be arranged concentrically with respect to the radial cross section of the rectifying unit, or may be arranged eccentrically. When the central axis of the rectifying unit and the central axis of the throttle part and the return part are coincident, the diameter of the throttle part is uniformly reduced and the return part is uniformly enlarged, so that the air flow is smoother. become. Therefore, in this case, an increase in pressure loss can be more reliably suppressed.

  Hereinafter, the air conditioning duct of the present invention will be described with reference to the drawings.

Example 1
The air-conditioning duct according to the first embodiment includes the above (1) to (3). A perspective view schematically showing the air conditioning duct of the first embodiment is shown in FIG. FIG. 2 schematically shows the inner surface of the air conditioning duct of the first embodiment.

  As shown in FIG. 1, the air-conditioning duct has a substantially rectangular tube shape. The wall thickness of the air conditioning duct is substantially constant. As shown in FIG. 2, the inner surface of the air conditioning duct of the first embodiment has a curved portion 1, a rectifying portion 2, a throttle portion 3, and a return portion 4.

The central axis L3 of the bending portion 1 has a curved shape. The central axis L1 of the rectifying unit 2, the central axis L4 of the throttle unit 3, and the central axis L5 of the return unit 4 are linear. The radial cross section of the rectifying unit 2 has a constant shape. The rectifying unit 2 has an axial length W1 of 94 mm. The radial cross-sectional area S2 of the rectifying unit 2 is 5290 mm ² .

As shown in FIGS. 1 and 2, the radial cross-sectional area of the throttle portion 3 decreases toward the downstream side of the air flow path. In other words, the radial cross-sectional area of the throttle portion 3 is maximized at the air flow channel upstream end (boundary portion with the rectifying unit 2), and the air flow channel downstream end (boundary portion with the return portion 4). , Called the lower end 30 of the aperture). The radial sectional area S1 of the diaphragm lower end 30 is 3325 mm ² . A line segment obtained by cutting the aperture portion 3 in the axial direction has an arc shape. Hereinafter, the radius of this circular arc is referred to as the aperture radius. The aperture radius in the air conditioning duct of Example 1 is 10 mm. The axial length W2 of the throttle unit 3 is also 10 mm. The radial cross-sectional area of the upstream portion (throttle stop suddenly changing portion) of the throttle portion 3 is rapidly reduced. The air flow path downstream side portion (throttle gradual change portion) of the throttle portion 3 gradually decreases in the radial cross-sectional area and is smoothly continuous with the return portion 4.

  The radial cross-sectional area of the return part 4 gradually increases toward the downstream side of the air flow path. The radial cross section of the air flow channel downstream end of the return portion 4 has the same shape as the radial cross section of the rectifying unit 2. The return portion 4 has an axial length W3 of 168 mm. As shown in FIG. 2, the central axis L <b> 1 of the rectifying unit 2 coincides with the central axes of the throttle unit 3 and the return unit 4. The angle θ formed by the central axis L1 and the straight line L2 is 2.97 °. The straight line L <b> 2 is on the same plane as the central axis L <b> 1, passes through the air flow channel downstream end of the return part 4, and is a straight line in contact with the return part 4.

In the air conditioning duct of the first embodiment, the radial cross-sectional area S1 of the throttle lower end 30 is 3325 mm ² , and the radial cross-sectional area S2 of the rectifying unit 2 is 5290 mm ² . Therefore, the area S1 is 9/20 or more of the area S2 and 9/16 or more.

  The radius r2 of a circle having an area equal to S2 is about 41.03 mm, and the axial length of the throttle unit 3 is 10 mm. Therefore, the axial length of the throttle portion 3 is ¼ or less of the radius of a circle whose area is equal to S2.

(Example 2)
The air conditioning duct of Example 2 includes the above (2) to (3). The air conditioning duct of the second embodiment is the same as the air conditioning duct of the first embodiment except for the shape of the throttle portion.

In the air conditioning duct according to the second embodiment, the radial cross-sectional area S1 of the lower end of the diaphragm is 2500 mm ² . A line segment obtained by cutting the throttle portion in the axial direction has an arc shape. The aperture radius in the air conditioning duct of Example 2 is 10 mm. The axial length W2 of the throttle part is also 10 mm.

In the air conditioning duct according to the second embodiment, the radial cross-sectional area S1 of the lower end of the throttle is 2500 mm ² , and the radial cross-sectional area S2 of the rectifying unit is 5290 mm ² . Therefore, the area S1 is 9/20 or more of the area S2.

  Further, similarly to the air conditioning duct of the first embodiment, the axial length of the throttle portion is 10 mm. Therefore, the axial length of the throttle portion is ¼ or less of the radius of a circle whose area is equal to S2. .

(Comparative example)
The air-conditioning duct of the comparative example is the same as the air-conditioning duct of Example 1 except that the air-conditioning duct does not have a throttle part and a return part, and the parts corresponding to the throttle part and the return part are replaced with a rectifying part. is there.

(Noise measurement test)
A noise generator was attached to the air flow path upstream end of the air conditioning duct of Example 1, the air conditioning duct of Example 2, and the air conditioning duct of the comparative example. The noise generator generated noise at each frequency of 315 Hz to 10000 Hz. A microphone was installed at the downstream end of the air flow path of these air conditioning ducts, and the noise generated by the noise generator and propagated through the air flow path of the air conditioning duct was measured. A graph showing the results of the noise measurement test is shown in FIG. In the graph shown in FIG. 3, the scale lines on the vertical axis are drawn at 10 dB intervals.

  As shown in FIG. 3, the air conditioning duct of Example 1 and the air conditioning duct of Example 2 can greatly reduce noise of 2500 Hz to 3150 Hz compared to the air conditioning duct of the comparative example. For example, the air conditioning duct of Example 1 can reduce the noise of 2500 Hz by 5.8 dB compared to the air conditioning duct of the comparative example. The air conditioning duct of Example 2 can reduce the noise of 2500 Hz by 12.1 dB compared to the air conditioning duct of the comparative example. From this result, it can be seen that according to the intake duct of the present invention, noise generated on the upstream side of the air flow path, that is, noise caused by the vehicle air conditioner can be greatly reduced.

(Pressure loss measurement test)
A vehicle air conditioner was attached to the upstream end of the air flow path of the air conditioning duct of Example 1, the air conditioning duct of Example 2, and the air conditioning duct of the comparative example, and the pressure loss due to each air conditioning duct was measured. Specifically, air was circulated through each air conditioning duct at a flow rate of 120 m ³ / hour by the vehicle air conditioner. And the pressure of the air which flows in into each air conditioning duct and the pressure of the air which flowed out from each air conditioning duct were measured, and the difference of both was made into the pressure loss by each air conditioning duct. Table 1 shows the pressure loss due to each air conditioning duct.

  As shown in Table 1, the pressure loss due to the air conditioning duct of Example 1 is a value close to the pressure loss due to the air conditioning duct of the comparative example. Further, the pressure loss due to the air conditioning duct of Example 2 is also sufficiently close to the pressure loss due to the air conditioning duct of the comparative example. Therefore, it can be seen that the air conditioning duct of the present invention can suppress an increase in pressure loss despite the provision of the throttle portion. That is, the air-conditioning duct of the present invention can reduce noise and sufficiently suppress an increase in pressure loss.

1 is a perspective view schematically illustrating an air conditioning duct of Example 1. FIG. It is a figure which represents typically the inner surface of the duct for an air conditioning of Example 1. FIG. It is a graph showing the result of a noise measurement test.

Explanation of symbols

1: curved part, 2: rectifying part, 3: restricting part, 4: returning part

Claims (4)

It is a duct for air conditioning that has a cylindrical shape and is connected to the downstream side of the air flow path of the vehicle air conditioner,
The inner surface of the air conditioning duct has a curved portion that is arranged on the vehicle air conditioner side and has a central axis that is curved, and is continuous with the downstream side of the air flow path of the curved portion, and the central axis is linear and radial. A rectifying section having a constant cross section, a throttle section that is continuous with the downstream side of the air flow path of the rectifying section and has a radial sectional area that decreases toward the downstream side of the air flow path, and a downstream side of the air flow path of the throttle section And a return section whose radial cross-sectional area gradually increases toward the downstream side of the air flow path,
The downstream portion of the throttle portion in the air flow path smoothly continues to the return portion,
The radial cross-sectional area S1 of the downstream end portion of the air flow path of the throttle portion is 9/20 or more of the radial cross-sectional area S2 of the rectifying portion,
An air-conditioning duct characterized in that the axial length of the throttle portion is ¼ or less of the radius of a circle having an area equal to S2.   The air conditioning duct according to claim 1, wherein the S1 is 9/16 or more of the S2.   The air conditioning duct according to claim 1, wherein an axial length of the rectifying unit is 30 mm or more.   The angle formed by the central axis L1 of the rectifying unit and the straight line L2 that is on the same plane as the L1 and passes through the air flow path downstream end of the return unit and contacts the return unit is 5 ° or less. Item 2. The air conditioning duct according to Item 1.

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