JP2006046113A - Shroud - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shroud allowing reduction of a primary component of fan rotation noise without decreasing a passing air volume to a heat exchanger. <P>SOLUTION: The shroud has a ring section 210 surrounding an outside diameter side of an axial-flow fan 100 for sending air with the opposite heat exchanger 1 situated upstream and an air introduction section 220 expanding from the ring section 210 upstream of blast air for introducing the blast air into the ring section 210, wherein a center of the ring second 210 is disposed eccentrically to a center of the air introduction section 220. A straightening plate 221 is provided on an inner surface of an air introduction section 220a which becomes a wider side by the eccentricity of the ring section 210. The plate has an arcuate shape concentric with the ring section 210 and projects to the upstream side of the blast air. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a shroud suitable for use in an axial blower mounted on, for example, a vehicle radiator.

  Conventionally, what is shown by patent documents 1 is known as a shroud of an axial blower used for a heat exchanger, for example. In other words, this shroud is provided with an opening on the narrow side of the air guide portion of the shroud and on the upstream side of the axial flow fan when the center of the axial flow fan is eccentric with respect to the heat exchanger.

Usually, in the case where the center of the axial fan is eccentric with respect to the heat exchanger, the rotational noise of the axial fan, particularly the deterioration of the primary component, becomes remarkable. However, according to the shroud, air is discharged from the opening. By introducing, the pressure balance on the upstream side of the axial fan can be corrected between the narrow side and the wide side of the shroud air guide, and the rotational noise of the axial fan, specifically here, the primary component and 3 The next component can be reduced.
JP-A-6-42498

  However, in the shroud, since air is introduced from the opening, the amount of air passing through the heat exchanger decreases, and strictly speaking, the performance of the heat exchanger decreases.

  In addition, in the above-mentioned Patent Document 1, there is further proposed a structure in which a rectifying plate is provided on the inner surface of the shroud air guide portion on the narrow side, which radiates from the center of the axial fan and protrudes inward. However, this is effective in reducing the secondary and quaternary components of the axial fan, and the primary component cannot be reduced.

  In view of the above problems, an object of the present invention is to provide a shroud that can reduce the primary component of fan rotation noise without reducing the amount of air passing through the heat exchanger.

  In order to achieve the above object, the present invention employs the following technical means.

  In the first aspect of the present invention, the ring portion (210) surrounding the outer diameter side of the axial fan (100) for blowing air with the opposing heat exchanger (1) as the upstream side, and the ring portion (210) And an air guide part (220) that guides the air to the ring part (210), and the center of the ring part (210) is the center of the air guide part (220). In the shroud arranged eccentrically with respect to the ring portion (210), the inner surface of the air guide portion (220a) on the wide side forms an arc shape concentric with the ring portion (210) along with the eccentricity of the ring portion (210). A rectifying plate (221) protruding upstream of the air is provided.

  When the air guide part (220) has a wide side (220a) and a narrow side (220b) due to the eccentricity of the ring part (210), the blown air flowing along the wide air guide part (220a) It is estimated that fan rotation noise (especially the primary component) is remarkably generated in order to oppose (interference) with the blowing air flowing in the axial direction of the axial fan (100) in the ring portion (210) region. .

  In the present invention, the flow of the blown air that is about to flow into the ring part (210) along the wide air guide part (220a) is suppressed by the rectifying plate (221), and the interference of the blown air as described above is suppressed. Since it can reduce, fan rotation noise (primary component) can be reduced. In addition, since the opening part is not provided in the air guide part (220) as in the above-mentioned Patent Document 1, when the shroud (200) is used for cooling the heat exchanger (1), the heat exchanger (1 ) Is not reduced.

  Here, as in the invention described in claim 2, when the inner diameter of the ring portion (210) is D and the length in the circumferential direction of the arc-shaped rectifying plate (221) is L, 0.34 ≦ It is preferable that L / D ≦ 0.44.

  Further, as in the invention described in claim 3, when the inner diameter of the ring portion (210) is D and the radius of curvature of the arc-shaped rectifying plate (221) is R, 0.57 ≦ R / D ≦ 0 .74 is good.

  Further, as in the invention described in claim 4, the protruding amount (h) of the current plate (221) is preferably 7 mm to 12 mm.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows a corresponding relationship with the specific means of embodiment description mentioned later.

(First embodiment)
A first embodiment of the present invention is shown in FIGS. 1 to 4, and a specific configuration will be described first. In the first embodiment, the shroud 200 of the present invention is applied to an axial fan (so-called electric fan) 10 for the radiator 1 formed by assembling the axial fan 100 and the motor 300. 1A is a front view, FIG. 1B is a plan view of FIG. 1A, and FIG. 2 is a schematic view showing the operation and effect of the current plate 221, FIG. 3 and FIG. 4 is a graph showing the fan rotation noise of the primary component with respect to L / D when the radius of curvature R of the current plate 221 and the level of the protrusion amount h are taken.

  The axial flow fan (hereinafter referred to as “blower”) 10 is fixed to the engine side of an automobile radiator (corresponding to a heat exchanger in the present invention) 1 by mounting portions 230 provided at four corners of the shroud 200. The cooling air is blown to the core portion 1a. Here, a so-called suction-type blower 10 that sucks blown air from the grill side of the vehicle toward the engine side, that is, from the core portion 1a of the radiator 1 to the axial flow fan 100 side.

  An axial fan (hereinafter referred to as a fan) 100 is made of a polypropylene material containing approximately 20% of glass fiber, and a boss portion 110 and a blade 120 are integrally formed by injection molding.

  The boss portion 110 has a cylindrical shape with one side closed, and a metal insert 111 made of aluminum is insert-molded at the central portion of the wall portion on the closed side. And the shaft hole 112 in which the shaft 310 of the motor 300 mentioned later is inserted is provided in the center part of the metal insert 111. As shown in FIG.

  A plurality of (seven in this embodiment) blades 120 extending radially are provided on the outer periphery of the boss portion 110, and here the outer diameter is set to 360 mm. Incidentally, the outer diameter dimension of the fan 100 is generally set in a range of about 250 mm to 400 mm according to the mountability to the vehicle and the required air blowing performance.

  The shroud 200 is made of a polypropylene material containing about 25 to 30% of glass fiber. The ring portion 210 and the air guide portion 220 described below are integrally formed by injection molding, including the attachment portion 230 to the radiator 1 described above. Has been.

  The ring part 210 is a part surrounding the outer diameter side of the fan 100, and a motor holding part (not shown) for holding the motor 300 is formed on the downstream side and the inner diameter side of the blown air. A minimum clearance (4 mm) that can avoid interference between the fan 100 and the ring portion 210 is secured, and the inner diameter D of the ring portion 210 is 368 mm.

  The air guide part 220 smoothly expands from the ring part 210 toward the upstream side (radiator 1 side) of the blown air, and the outline (outer shape) forms a rectangular shape corresponding to the core part 1 a of the radiator 1. . And, in order to avoid interference with vehicle-side parts when mounted on a vehicle, the center of the ring part 210 is arranged eccentrically with respect to the center of the air guide part 220 (here, eccentric to the right side in FIG. 1). Has been.

  With the eccentricity of the ring part 210, the air guide part 220 is divided into a wide area 220a (left side in FIG. 1) and a narrow side 220b (right side in FIG. 1). A characteristic is provided in that a rectifying plate 221 is provided on the inner surface of the air guide section 220a on the side.

  That is, the rectifying plate 221 has a circular arc shape concentric with the ring portion 210 and is a plate member (plate thickness 2 mm) protruding upstream of the blown air, and is formed integrally with the wide air guide portion 220a. I try to do it. Here, two rectifying plates 221 are provided in the vertical direction of FIG. As for the dimensions of each part of the current plate 221, the circumferential length is L, the radius of curvature (that is, corresponding to the distance from the center of the ring part 210) is R, and the protruding amount is h for the following explanation. To do.

  The motor 300 is fixed to the motor holding portion of the ring portion 210, and the shaft 310 of the motor 300 is fitted into the shaft hole 112 of the fan 100, and the motor 300 and the fan 100 are fixed. Incidentally, the motor 300 is a well-known DC ferrite motor, and is connected to a controller (not shown). The controller varies the average current value by changing the ratio of the ON / OFF time of the current flowing to the motor 300, and varies the number of rotations of the directly connected fan 100 according to the required cooling capacity of the radiator. Adjust the air flow. Note that, in the normal range of the blower 10, the rotational speed is set at approximately 1700 rpm.

  In the blower 10 formed in this way, the fan 100 is rotated by the operation of the motor 300, the cooling air is blown to the core portion 1 a of the radiator 1, and heat dissipation from the cooling water in the radiator 1 is promoted. .

  By the way, in the state before applying this invention (rectifier plate 221), when the ring part 210 of the shroud 200 is decentered, the wide side air guide part 220a and the narrow side air guide part 220b can be formed. As shown in FIG. 5 (bench check result when the fan 1 is mounted on the radiator 1), fan rotation noise (primary component = fan 100 rotation frequency 28 Hz × 7 blades≈200 Hz region noise) is remarkable. Occurs. This fan rotation noise may be amplified during propagation to the vehicle, which is a problem. As shown in FIG. 6, this occurs because the blown air flowing along the wide air guide portion 220a faces (interferences) with the blown air flowing in the direction of the rotation axis of the fan 100 in the ring portion 210 region. Presumed to be.

  In the present invention, as shown in FIG. 2, the flow of blown air that is about to flow into the ring portion 210 along the wide air guide portion 220a is suppressed by the rectifying plate 221, and the interference of the blown air as described above is performed. Therefore, fan rotation noise (primary component) can be reduced.

  Specifically, as shown in FIG. 3, various curvature radii R of the rectifying plate 221 are various with respect to the ratio (L / D) between the circumferential length L of the rectifying plate 221 and the inner diameter D of the ring portion 210. In the modified one (projection amount h of the rectifying plate 221 is 7 mm), when the fan rotation noise of the primary component is examined, a good noise reduction effect is obtained when the L / D is in the range of 0.34 to 0.44. It was.

  As for the radius of curvature R of the rectifying plate 221, the noise reduction effect is higher as it is set closer to the ring part 210, and a maximum reduction effect of approximately 4.5 dB is obtained when R = 211 mm, and R271 mm. The effect was recognized even to the thing. If this is grasped by the ratio (R / D) with the inner diameter D of the ring part 210, it is considered that R / D is in a range of 0.57 to 0.74.

  Further, as shown in FIG. 4, when the protruding amount h of the rectifying plate 221 is increased from 7 mm to 12 mm (R = 231 mm, 251 mm), the flow along the wider air guide portion 220a and the ring portion 210 will flow. Interference with the flow is reduced, and a large reduction effect (Δ2.5 to Δ4 dB) was obtained.

  Since the present invention does not provide an opening in the air guide portion 220 as in the above-mentioned Patent Document 1, the amount of air passing through the radiator 1 (core portion 1a) is not reduced.

(Other embodiments)
In the first embodiment, the rectifying plate 221 has been described as being integrally formed with the wide air guide portion 220a. However, the rectifying plate 221 may be formed separately.

  The outline of the air guide section 220 is not limited to a rectangular shape, and may be a circular shape, an elliptical shape, or the like.

  The fan 100 is the electric blower 10 that is rotated by the motor 300. However, the fan 100 is not limited thereto, and may be an engine fan that is rotated by the driving force of the vehicle engine, for example.

  Further, the fan 100 has been described as supplying the blown air to the radiator 1. However, the present invention is not limited to this, and a condenser for condensing refrigerant of an air conditioner, an oil cooler for cooling oil, an intercooler for cooling intake air, and the like. It may be intended for other heat exchangers.

(A) which shows the whole structure of an axial-flow fan is a front view, (b) is a top view of (a). It is a schematic diagram which shows the effect of a baffle plate. It is a graph which shows the fan rotation noise of the primary component with respect to L / D when the level of the curvature radius R of a baffle plate is taken. It is a graph which shows the fan rotation noise of the primary component with respect to L / D when the level of the protrusion amount h of a baffle plate is taken. It is a graph which shows the noise with respect to the frequency before applying this invention. In FIG. 5, it is a schematic diagram which shows the cause which fan rotation noise appears notably.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Radiator 10 Axial flow fan 100 Axial flow fan 200 Shroud 210 Ring part 220 Air guide part 220a Wide side air guide part 221 Current plate

Claims (4)

A ring portion (210) surrounding the outer diameter side of the axial fan (100) for blowing air with the opposing heat exchanger (1) as an upstream side;
An air guide part (220) that expands from the ring part (210) to the upstream side of the blown air and guides the blown air to the ring part (210);
In the shroud in which the center of the ring part (210) is arranged eccentrically with respect to the center of the air guide part (220),
Along with the eccentricity of the ring part (210), the inner surface of the air guide part (220a) on the wide side forms an arc shape concentric with the ring part (210) and protrudes upstream of the blown air. A shroud provided with a current plate (221).   0.34 ≦ L / D ≦ 0.44, where D is the inner diameter of the ring part (210) and L is the length in the circumferential direction of the rectifying plate (221) having an arc shape. The shroud according to claim 1.   The inner diameter of the ring portion (210) is D, and the radius of curvature of the arc-shaped rectifying plate (221) is R, 0.57≤R / D≤0.74. The shroud of claim 1 or 2.   The shroud according to any one of claims 1 to 3, wherein a protruding amount (h) of the rectifying plate (221) is 7 mm to 12 mm.

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