JP3807144B2 - Centrifugal blower - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a centrifugal blower having a centrifugal fan that has a large number of blades (blades) around a rotating shaft and blows out air sucked from a longitudinal one end side of the rotating shaft toward a radially outward side by centrifugal force. It is effective when applied to a vehicle air conditioner.
[0002]
[Prior art]
As a cause of noise in the centrifugal blower, there is known interference between the backflow air and the intake air generated in the vicinity of the winding start portion (nose portion) of the scroll casing.
As a means for preventing the interference between the backflow air and the intake air, for example, in the invention described in Japanese Patent Application Laid-Open No. 7-224955, the stay member located near the nose portion among the three stay members supporting the centrifugal fan By using a flat fan shape, the backflow air is blocked and the backflow air and the intake air are prevented from interfering with each other.
[0003]
[Problems to be solved by the invention]
However, in the invention described in the above publication, when the pressure loss (ventilation resistance) of the ventilation system connected to the centrifugal blower is large and the rotational speed of the centrifugal fan is small, the flow of backflow and intake air is small. However, when the pressure loss of the ventilation system is small and the centrifugal fan has a large number of airflows, the flat fan-shaped stay member has sufficient ventilation resistance. There is a problem that it is difficult to secure the air flow rate.
[0004]
The present invention has been made in view of the above points, and it is an object of the present invention to reduce ventilation resistance by a stay member while preventing interference between backflow air and intake air.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, the cross-sectional shape of the stay members (241 to 243) for fixing the driving means (240) to the scroll casing (230) is It is linear or an airfoil, and the front edge side is located in the rotation direction retreat side of the centrifugal fan (220).
[0006]
Thereby, even when the pressure loss of the ventilation system is small and the amount of blown air with a large rotational speed of the centrifugal fan (220) is large, the stay members (241 to 243) have a large ventilation resistance. Can be prevented.
On the other hand, when the pressure loss of the ventilation system is large and the rotational speed of the centrifugal fan (220) is small, the airflow is prevented from interfering (frictioning) with the backflow air and the stay member (241). Since the backflow air can flow along the blade surfaces ˜243), the backflow air can be smoothly merged with the intake air and re-inhaled without friction between the backflow air and the intake air.
[0007]
As described above, according to the present invention, it is possible to reduce the ventilation resistance by the stay members (241 to 243) while preventing the interference between the backflow air and the intake air and reducing the noise.
Incidentally, the reference numerals in parentheses of each means described above are an example showing the correspondence with the specific means described in the embodiments described later.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
In the present embodiment, the centrifugal blower according to the present invention is capable of classifying the interior air (hereinafter abbreviated as “inside air”) and the exterior air (hereinafter abbreviated as “outside air”) into the interior and the outside of the vehicle. This is applied to a vehicle air conditioner.
FIG. 1 is a schematic diagram of a vehicle air conditioner 100 according to the present embodiment, and 110 is an air conditioner casing that constitutes a passage of air blown out toward the vehicle interior. On the upstream side of the air flow of the air conditioning casing 110, an outside air introduction port 111 for introducing outside air and first and second inside air introduction ports 113 and 112 for introducing inside air are provided, and the outside air introduction port 111 and the first inside air introduction are provided. The opening 113 is opened / closed by the first inside / outside air switching door 114, and the second inside / outside air inlet 112 is opened / closed by the second inside / outside air switching door 115.
[0009]
Reference numeral 200 denotes a centrifugal blower (hereinafter abbreviated as a blower) that sucks the inside air and the outside air and blows the sucked air toward the vehicle interior. Is divided into two air passages 116 and 117. The details of the blower 200 will be described later.
[0010]
Further, an evaporator (air cooling means) 119 that cools the air flowing through the air passages 116 and 117 is disposed on the downstream side of the air flow of the blower 200. The air flow of the evaporator 119 includes an evaporator. A heater core (air heating means) 120 for heating the air that has passed through 119 is disposed.
Note that the vehicle air conditioner according to the present embodiment employs a so-called reheat type in which the temperature of air blown into the vehicle interior is adjusted by adjusting the degree of air heating in the heater core 120.
[0011]
In addition, on the downstream side of the air flow of the heater core 120, a communication opening 121 for communicating the two air passages 116, 117, a defroster opening 122 for blowing air toward the windshield (not shown) of the vehicle, and the upper body of the occupant A face opening 123 that blows out air and a foot opening 124 that blows out air toward the lower body of the occupant are formed, and the openings 121 to 124 are opened and closed by doors 125 to 128.
[0012]
In general, in a vehicle air conditioner, a ventilation system viewed from the blower 200 is used when air is blown from the defroster opening 122 and the foot opening 124 compared to when blowing air from the face opening 123. The pressure loss increases.
Next, the blower 200 will be described.
As shown in FIG. 1, the blower 200 is arranged coaxially with the first centrifugal fan (hereinafter abbreviated as “first fan”) 210 on the outside air introduction port 111 side and the first fan 210 on the second inside air introduction port 112 side. Second centrifugal fan (hereinafter abbreviated as “second fan”) 220, spiral scroll casing 230 that houses both fans 210 and 220, and electric motor (drive means) that rotationally drives both fans 210 and 220 240.
[0013]
In the present embodiment, the fan diameter of the first fan 210 is smaller than the fan diameter of the second fan 220.
Here, as shown in FIG. 2, the fans 210 and 220 rotate a large number of blades 211 and 221 arranged around the rotation shaft 200a around the rotation shaft 200a of the electric motor 240. The centrifugal fan blows out the air sucked from the direction of the rotating shaft 200a toward the radially outer side of the fans 210 and 220.
[0014]
Further, in the scroll casing 230 (hereinafter abbreviated as the casing 230) 230, at one end side in the longitudinal direction of the rotating shaft 200a (second fan 220 side), as shown in FIG. 231 is formed, and a suction port 232 for the first fan 210 is formed at the other end in the longitudinal direction of the rotating shaft 200a (on the first fan 210 side).
[0015]
Then, the casing 230 collects air blown from both the fans 210 and 220 and blows it toward the evaporator 119 side, as shown in FIG. The electric motor 240 is formed in a spiral shape so as to increase the area, and the electric motor 240 is disposed at a substantially central portion of the suction port 231 for the second fan 220.
[0016]
The electric motor 240 is supported and fixed to the casing 230 by three stay members 241 to 243 extending from the outer edge portion (bell mouth 231a) of the suction port 231 toward the central portion of the suction port 231. The three stay members 241 to 243 are referred to as a first stay 241, a second stay 242, and a second stay 243 in order from the winding start (nose portion N) toward the forward side in the rotational direction of the fan 220.
[0017]
And the cross-sectional shape of the stay member (all of the first to third stays 241 to 243 in this embodiment) existing at least from the nose portion N to the portion advanced by 180 ° toward the rotation direction advance side of the fan 220 is: As shown in FIG. 4, the airfoil is configured so that its leading edge is located on the retreating side of the fan 220 in the rotation direction, and its chord direction D is orthogonal to the longitudinal direction of the rotation shaft 200a. It is substantially parallel to the direction to do.
[0018]
Incidentally, as is well known, a wing refers to an object having a shape that generates a lift much larger than the resistance, and a cross-sectional shape parallel to the direction of the lift of the flow is referred to as a wing shape. The chord is a straight line connecting the leading and trailing edges of the airfoil (extracted from the University of Tokyo Press).
In the present embodiment, as shown in FIG. 5, the stay member (first stay 241) located in the vicinity of the nose portion N is made hollow to form the air passage 241a, and as shown in FIG. Air taken from a cooling air intake port 233 provided in the vicinity is led to the electric motor 240 through the air passage 241a to cool the electric motor 240.
[0019]
Further, in the present embodiment, as shown in FIG. 1, a filter F that removes dust in the intake air and purifies the air is disposed on the side of the blower 200 and the suction port 232.
Next, features of the present embodiment will be described.
According to the present embodiment, since the cross-sectional shape of the stay members (first to third stays 241 to 243) is a wing shape, the air flow rate is low and the fan 220 has a large rotational speed. Even when there is a large amount of air, it is possible to prevent the stay members (first to third stays 241 to 243) from having large ventilation resistance as shown in FIG.
[0020]
On the other hand, when the pressure loss of the ventilation system is large and the rotational speed of the fan 220 is small, the airflow is prevented from interfering (friction) with the backflow air and the intake air as shown in FIG. In addition, since the backflow air can flow along the blade surface 241b, the backflow air can smoothly merge with the intake air and can be sucked again without friction between the backflow air and the intake air.
[0021]
Therefore, it is possible to reduce ventilation resistance by the stay members (first to third stays 241 to 243) while preventing noise by preventing interference between the backflow air and the intake air.
Incidentally, FIG. 6 (a) shows the air flow when the pressure loss of the ventilation system is large and the fan rotation speed is small and the amount of blown air is small and the cross-sectional shape of the stay member S is rectangular. FIG. 6B shows a case where the pressure loss of the ventilation system is small and the fan rotation speed is large and the amount of blown air is large, and the cross-sectional shape of the stay member S is rectangular. As can be seen from both figures, when the pressure loss of the ventilation system is large and the fan speed is small, the airflow can be prevented from interfering with the backflow air and the intake air. It can be seen that the stay member S has a large ventilation resistance when the pressure loss of the ventilation system is small and the air flow rate is large with a large number of rotations of the fan.
[0022]
3 is a view as seen from the direction of arrow A in FIG. 1. As is clear from this figure, the intake air is not sucked from the entire area of the suction port 231, but is a stay member (first to third stays 241 to 241). 243) is generated as a backflow air. Therefore, as in the present embodiment, when the stay member (first to third stays 241 to 243) is a wing shape, the airflow resistance is effectively reduced while preventing interference between the backflow air and the intake air and reducing noise. Can be reduced.
[0023]
By the way, in the above-described embodiment, the blower according to the present invention is applied to the vehicle air conditioner of the inside / outside air two-layer flow type. However, the present invention can also be applied to a normal air conditioner that mixes the inside air and the outside air and blows air. it can.
Moreover, in the above-mentioned embodiment, although the several fan 210,220 was the air blower arrange | positioned coaxially, it is applicable also to the air blower which has only one fan.
[0024]
Moreover, the application of the blower according to the present invention is not limited to the air conditioner, and can be applied to other blowers such as a ventilation fan.
Moreover, in the above-mentioned embodiment, although the cross-sectional shape of the 1st-3rd stays 241-243 was an airfoil, it may be streamlined. Streamline refers to a shape that has low resistance and is unlikely to peel (extracted from the Fluid Engineering Tokyo University Press).
[0025]
In the above-described embodiment, the cross-sectional shapes of all the stay members (first to third stays 241 to 243) are wing-shaped, but at least 180 ° advanced from the nose portion N to the forward side in the rotation direction of the fan 220. The cross-sectional shape of the stay member first to third stays 241 to 243) existing between the portions may be an airfoil or a streamline.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an air conditioner.
FIG. 2 is a front view of the fan.
FIG. 3 is a schematic diagram of a blower.
FIG. 4A is a schematic diagram showing an air flow when the pressure loss of the ventilation system is large and the fan rotation speed is small, and the air flow is small, and FIG. 4B is a pressure loss of the ventilation system. It is a schematic diagram which shows an air flow when there is much ventilation volume with small and high rotation speed of a fan.
FIG. 5 is a sectional view of a first stay.
FIG. 6A is a schematic diagram showing an air flow when the pressure loss of the ventilation system is large and the fan rotation speed is small, and the air flow is small, and FIG. 6B is a pressure loss of the ventilation system. It is a schematic diagram which shows an air flow when there is much ventilation volume with small and high rotation speed of a fan.
[Explanation of symbols]
210 ... first fan, 220 ... second fan, 241 ... first stay,
242 ... Second stay, 243 ... Second stay.

Claims (4)

A centrifugal fan (220) having a plurality of blades (221) around the rotating shaft (200a), and blowing out the air sucked from the longitudinal one end side of the rotating shaft (200a) toward the radially outward side;
A spiral scroll casing that houses the centrifugal fan (220), collects air blown out from the centrifugal fan (220), and has a suction port (231) formed at the longitudinal end of the rotating shaft (200a). 230)
A driving means (240) positioned substantially in the center of the suction port (231) and driving the centrifugal fan (220) to rotate;
The driving means (240) is fixed to the scroll casing (230) by stay members (241 to 243) extending from the outer edge of the suction port (231) toward the center of the suction port (231). And
Furthermore, the cross-sectional shape of the stay members (241 to 243) is streamlined or airfoil, and the front edge side thereof is located on the retreating side in the rotational direction of the centrifugal fan (220). Blower. The stay members (241, 242) are provided between portions that are advanced 180 ° from the winding start portion (N) of the scroll casing (230) to the forward side in the rotational direction of the centrifugal fan (220). The centrifugal blower according to claim 1. The chord direction (D) of the stay members (241 to 243) having a cross-sectional shape formed in a streamlined or airfoil shape is substantially parallel to a direction orthogonal to the longitudinal direction of the rotating shaft (200a). The centrifugal blower according to claim 1 or 2. A plurality of the stay members (241 to 243) are provided around the drive means (240),
The cross-sectional shapes of all of the plurality of stay members (241 to 243) are streamlined or airfoil, and the front edge side thereof is positioned on the receding direction of the centrifugal fan (220). The centrifugal blower according to any one of claims 1 to 3.

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