JP2013060916A - Centrifugal fan, and air conditioner using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce separation of inflow air caused by collision with an edge on a fun suction side of a blade to discharge airflow smoothly, using a two-dimensional shaped blade.SOLUTION: A turbofan 1 includes: a main plate 12; a ring 13 facing the main plate 12; and a plurality of blades 20 lying between outer peripheries of the main plate 12 and the ring 13. The turbofan includes a fan suction port 14 in the center. The blade 20 is formed in a two-dimensional shape. A chord line L2 of a part V2 positioned on the fun suction port 14 side of the blade 20 is offset on a rotation direction side further than a chord line L1 of a part V1 positioned on a main plate 12 side.

Description

  The present invention relates to a centrifugal fan having a ring portion facing a main plate portion, and a plurality of blades straddling between the main plate portion and the outer peripheral portion of the ring portion, and having a fan suction port at a central portion.

  Conventionally, in an air conditioner, a refrigeration apparatus, and the like, a centrifugal fan is used to blow air that has been cooled, heated, humidified, or dehumidified (see, for example, Patent Document 1). For example, as shown in FIG. 11, this centrifugal fan normally has a plurality of blades (blades) 103 radially extending between outer peripheral portions of a main plate portion (main plate) 101 and a ring portion (side plate) 102 in a casing. It is comprised from the arranged impeller and the motor which drives the said impeller.

  In this case, the ring portion 102 side coupling position at the rear edge of each blade 103 is offset by a predetermined amount in the counter-rotating direction of the impeller from the main plate portion 101 side coupling position, and a so-called three-dimensional curved surface is drawn. It is said to be a wing.

  As a result, when the motor is driven to rotate the impeller of the centrifugal fan, each blade of the impeller pressurizes the air from the inner peripheral side space to the outer peripheral side space, and outwards in the radial direction of the impeller. The air is sucked into the space on the inner peripheral side of the impeller from the air suction port that opens in the axial direction of the blowing and rotating shaft.

JP-A-5-39930

  However, if the blade (blade) shape of the impeller is three-dimensional, the blade outflow angle of the main plate portion 101 and the blade outflow angle on the ring portion 102 side are different as shown in FIG. For this reason, the direction and size of the air flowing out from the main plate portion 101 side and the ring portion 102 side are different at the trailing edge of the blade 103, so that a velocity gradient is generated and the air flow is disturbed. Thereby, a loud noise is emitted. In addition, when the air flow is disturbed when installed in an air conditioner, the fluid noise due to the interference of the fins rises when it flows into the heat exchanger in which the fins are arranged in parallel in units of several millimeters. There's a problem.

  Furthermore, since it is configured with the same dimensions and the same material and becomes heavier than the two-dimensional case, the load on the motor is increased when starting the centrifugal fan, resulting in power consumption. Incurs an increase in volume. Moreover, there is a problem that the material cost for configuring the wing increases.

  The present invention has been made in order to solve the conventional technical problem, and the two-dimensional blade reduces the occurrence of separation of incoming air caused by collision with the fan suction side edge of the blade, thereby achieving smoothness. A centrifugal fan capable of discharging a simple air flow and an air conditioner using the centrifugal fan are provided.

  In order to solve the above-mentioned problems, the present invention has a main plate portion, a ring portion facing the main plate portion, and a plurality of wings straddling between the main plate portion and the outer peripheral portion of the ring portion, and a central portion. In a centrifugal fan having a fan suction port, the blade has a two-dimensional shape, and the chord line of the portion located on the fan suction port side of the blade rotates more than the chord line of the portion located on the main plate side. It is offset in the direction side.

  According to the invention of claim 2, in the above invention, the inlet angle which is an angle formed by the chord line of the portion located on the fan suction port side of the blade and the center line is larger than the inlet angle of the portion located on the main plate portion side. It is characterized by becoming smaller.

  The invention of claim 3 has a main plate portion, a ring portion facing the main plate portion, a plurality of blades straddling between the main plate portion and the outer peripheral portion of the ring portion, and a fan suction port in the center portion. In the centrifugal fan, the blade has a two-dimensional shape, and an inlet angle that is an angle formed by a chord line and a center line of a portion located on the fan suction port side of the blade is located on the main plate portion side It is characterized by being smaller than the entrance angle.

  The invention of claim 4 has a main plate portion, a ring portion facing the main plate portion, and a plurality of blades straddling between the main plate portion and the outer peripheral portion of the ring portion, and has a fan suction port in the center portion. In the centrifugal fan, the blade has a two-dimensional shape, the portion of the blade located on the fan suction port side is tapered, and the surface on the counter-rotation direction side is inclined compared to the surface on the rotation direction side. Is characterized by being sluggish.

  According to a fifth aspect of the present invention, in each of the above-described inventions, the blade includes a first region which is a portion located on the main plate portion side, and a second region which is a portion located on the fan suction port side. The size of the region in the height direction of the wing is characterized by being larger than the second region.

  An air conditioner according to a sixth aspect of the present invention is a centrifugal fan according to each of the above inventions, an air suction port that is formed corresponding to the fan suction port of the centrifugal fan, and sucks air from the conditioned chamber, and a blower side of the centrifugal fan And an air outlet for blowing the air heat-exchanged with the heat exchanger into the conditioned room.

  According to the centrifugal fan of the present invention, the fan has a main plate portion, a ring portion facing the main plate portion, and a plurality of blades straddling between the main plate portion and the outer peripheral portion of the ring portion, and a fan suction port in the center portion. The blade has a two-dimensional shape, and the chord line of the portion located on the fan suction port side of the blade has a rotational direction side than the chord line of the portion located on the main plate portion side. In other words, the inlet angle, which is the angle formed by the chord line of the portion of the blade located on the fan inlet side of the blade and the center line as in claim 2, is the portion of the portion located on the main plate portion side. Since it is comprised so that it may become smaller than an entrance angle, the angle of the surface of the edge part by the side of the fan suction of a wing | blade can be closely approached with respect to the inflow angle of the air which flows in into an inside from the peripheral part of a fan suction port.

  Further, as in the invention of claim 4, the portion of the blade located on the fan suction port side is tapered, and the inclination of the surface on the counter-rotating direction side is made slower than the surface on the rotating direction side. Accordingly, the angle of the edge surface on the fan suction side of the blade can be made closer to the inflow angle of the air flowing into the inside from the peripheral portion of the fan suction port.

  Therefore, the edge on the fan suction side of each blade can be formed along the flow of air flowing into the inside from the peripheral portion of the fan suction port, and air separation (air) by colliding with the edge of the blade (Disturbance of flow) can be reduced. Thereby, the fluid sound caused by the separation of air can be reduced, a smooth air flow can be realized, and the discharge air volume can be increased. Therefore, the number of fan rotations can be reduced, and the fluid sound and power consumption can be further reduced.

  In addition, according to the first to fourth aspects of the present invention, since the wing has a two-dimensional shape, molding is easy, and weight reduction can be realized.

  According to the invention of claim 5, in addition to the above-mentioned inventions, the blade is composed of a first region which is a portion located on the main plate portion side and a second region which is a portion located on the fan suction port side. By making the dimension in the height direction of the blades in the first region larger than that in the second region, it is possible to ensure the amount of air discharged by the rotation of each blade.

  According to the air conditioner of the invention of claim 6, the centrifugal fan of each of the above inventions, an air suction port that is formed corresponding to the fan suction port of the centrifugal fan, and sucks air from the conditioned room, By providing a heat exchanger arranged on the blow-out side and an air outlet through which air exchanged with the heat exchanger is blown out into the conditioned room, turbulent air flow caused by air separation is heat exchanged The inconvenience that is blown out to the heat exchanger can be reduced, and by the smooth inflow of airflow, the interference sound with the heat exchanger can be reduced, and the generation of noise can be suppressed.

It is a vertical side view of the air conditioner to which the centrifugal fan of the present invention is applied. It is a perspective view of the centrifugal fan to which the present invention is applied. It is a vertical side view of a centrifugal fan. It is the figure which showed the blade cross section of a different height position using the perspective view from the arrow Y direction of FIG. It is the figure which showed the blade | wing cross section of a different height position using the perspective view of the state which cut | disconnected FIG. 2 in the direction of arrow Z. FIG. It is a plane sectional view in each part of a wing explaining an entrance angle. It is a figure explaining the angle | corner which each chord line | wire which the fan inlet side and the main board part side comprise. It is a figure explaining peeling of air. It is a figure explaining peeling of air. It is a perspective view explaining the height dimension of a wing. It is a fragmentary sectional view of the conventional impeller.

  Hereinafter, embodiments of the present invention will be described in detail. 1 is a longitudinal side view of an air conditioner AC to which the turbo fan 1 of the present invention is applied, FIG. 2 is a perspective view of the turbo fan 1 to which the present invention is applied, FIG. 3 is a longitudinal side view of the turbo fan 1, FIG. FIG. 5 is a view showing a blade section of the turbofan 1. In this embodiment, a turbo fan 1 will be described as an example of a centrifugal fan. The centrifugal fan is not limited to this, and may be a sirocco fan or the like.

  The air conditioner AC of the embodiment is configured by housing each part in a box-shaped casing 2 made of sheet metal. The casing 2 is suspended from the ceiling by suspension bolts and buried in the back of the ceiling, and the lower end of the casing 2 has a height substantially equal to the ceiling of the conditioned room. A turbo fan 1 that sucks air from the conditioned room 3 and a motor 10 that drives the turbo fan 1 are disposed in the casing 2.

  In the casing 2, a fin-and-tube heat exchanger 6 bent in a polygonal shape is disposed so as to surround the turbofan 1 and located on the blow-out side of the turbofan 1. The lower surface 2A of the casing 2 is substantially flush with the ceiling plate of the air-conditioned room, and an air suction port 4 for sucking air from the conditioned room 3 is formed at the center thereof. An air outlet 5 is formed in the outer edge portion located on the periphery (the side away from the rotation center of the turbo fan 1 in the horizontal plane) to blow out the air heat-exchanged with the heat exchanger 6 into the conditioned chamber 3. Below the heat exchanger 6 of the casing 2, a bell mouth 7 that is gradually reduced in diameter is attached to guide the air sucked from the air suction port 4 to the turbofan 1.

  The turbofan 1 includes a main plate portion 12, an annular ring portion 13 facing the main plate portion 12, and a plurality of blades 20 in the present embodiment. Each wing 20 has one end fixed to the outer peripheral portion of one surface of the main plate portion 12 on the ring portion 13 side, and the outer peripheral edge of the other end is joined by the ring portion 13, so that the main plate portion 12 and the ring portion 13 It is provided straddling between the outer peripheral portions.

  The main plate portion 12 is formed with a bulging portion 12A which is located at the center and bulges toward the ring portion 13, and the motor 10 is accommodated in the bulging portion 12A. The rotation shaft of the motor 10 is provided so as to extend in a direction substantially orthogonal to the main plate portion 12 and the ring portion 13 of the turbofan 1, and the end portion of the rotation shaft is opposite to the ring portion 13 of the main plate portion 12. On the side surface, it is fixed to the approximate center of the bulging portion 12A of the main plate portion 12.

  The inner diameter of the edge of the bell mouth 7 of the casing 2 is smaller than the inner diameter of the ring portion 13 of the turbofan 1, and the edge of the bell mouth 7 enters the ring portion 13 and rotates. It is configured by overlapping predetermined dimensions in the axial direction.

  As a result, the edge of the ring portion 13 facing the bell mouth 7 on the bell mouth 7 side is located at the center of the turbofan 1 and constitutes the fan suction port 14. The outer peripheral side of the turbo fan 1, that is, the blade trailing edge 21 side of each blade 20 constitutes the fan outlet 15.

  Each blade 20 is arranged at an equiangular position with respect to the rotation center (rotation axis). In the blade 20, the blade leading edge 22, which is an edge near the rotation center (rotation axis), is more in the rotation direction (the arrow in FIG. 2) than the blade trailing edge 21, which is an edge far from the rotation center (rotation axis) of the blade 20. ). That is, the blade trailing edge 21 is positioned on the delay side in the rotational direction with respect to the blade leading edge 22.

  The blade 20 has a two-dimensional shape in which the blade leading edge 22 and the blade trailing edge 21 are both orthogonal to the main plate portion 12 and the ring portion 13. As shown in the vertical side view of FIG. 3, the blade 20 includes a first region P1 that is a portion located on the main plate portion 12 side, and a second region P2 that is a portion located on the fan suction port 14 side. Consists of.

  In the first region P1 portion located on the main plate portion 12 side, the cross section in the direction (X-axis direction in the drawing) orthogonal to the rotation axis direction (Y-axis direction in the drawing) of the blade 20 is at any height position. The cross-sectional shape is the same (single cross-sectional shape) (except for the joint portion 16 between the blade 20 and the ring portion 13). In contrast, in the second region P2 portion located on the fan suction port 14 side, the blade leading edge 22 side gradually decreases toward the fan suction port 14, and the blade thickness dimension is tapered. . That is, in the second region P2, the cross section in the direction (X-axis direction in the drawing) orthogonal to the rotation axis direction (Y-axis direction in the drawing) of the blade 20 extends from the main plate portion 12 side to the fan suction port 14 side. It becomes progressively smaller (ie it has a plurality (two or more) of different cross-sectional shapes).

  FIG. 4 shows cross sections S1 and S2 at different heights (directions orthogonal to the rotation direction) of the blade 20 in the second region P2 of the blade 20 when FIG. 2 is viewed from the direction of the arrow Q. The cross section S1 shows a cross section on the main plate portion 12 side in the second region P2, and the cross section S2 shows a cross section located closer to the fan suction port 14 than the cross section S1.

  FIG. 5 shows cross sections S3 and S4 at different heights (directions orthogonal to the rotational direction) of the blade 20 in the second region P2 of the blade 20 in a state where FIG. 2 is cut in the direction of the arrow R, respectively. Yes. The cross section S3 shows a cross section on the main plate portion 12 side in the second region P2, and the cross section S4 shows a cross section located closer to the fan suction port 14 than the cross section S3.

  At this time, as shown particularly in FIG. 5, the cross-sectional shape of the second region P2 of the blade 20 is such that the maximum blade thickness (T4) of the cross section located on the fan suction port 14 side is the cross section of the main plate portion 12 side. It gradually decreases based on the maximum blade thickness (T3).

  Further, the end of the second region P2 on the fan suction port 14 side, that is, the portion located on the fan suction port 14 side of the blade 20 is shown in the cross-sectional view in each part (V1, V2) of FIG. The blade chord line (line connecting the blade leading edge 22 and the blade trailing edge 21) L2 of the portion (V2 in the figure) located on the fan inlet 14 side of the blade 20 and the center line C2 of the blade leading edge 22 portion are The inlet angle θ2 that is the angle formed is smaller than the inlet angle θ1 that is the angle formed by the chord line L1 of the portion (V1 in the figure) located on the main plate portion 12 side and the center line C1 of the blade leading edge 22 portion. It is formed as follows.

  That is, as shown in the sectional view of each part (V1, V2) in FIG. 7, the part (V2 in the figure) located on the fan suction port 14 side of the blade 20 is located on the chord line L2 and the main plate part 12 side. An angle α formed by the chord line L1 of the portion (V1 in the figure) is offset to the rotation direction side.

  In this way, the chord line L2 of the portion (V2 in the figure) located on the fan suction port 14 side of the blade 20 rotates more than the chord line L1 of the portion (V1 in the figure) located on the main plate portion 12 side. By being offset to the side, as shown in the left side of FIG. 8, the end of the blade 20 on the fan suction port 14 side (excluding the portion connected to the ring portion 13) is on the rotational direction side 23. The inclination of the surface 24 on the counter-rotating direction side is slower than that of the surface.

  As a result, air flowing into the turbofan 1 from the peripheral edge of the fan suction port 14 flows into the fan suction port 14 at a predetermined inflow angle from an oblique direction. The angle of the edge surface 25 on the fan inlet 14 side of the blade 20 can be made closer to that shown in FIG.

  Therefore, the edge on the fan suction port 14 side of each blade 20 can be formed along the flow of air flowing into the inside from the peripheral portion of the fan suction port 14, as shown in the right side of FIG. Generation of air separation (turbulence of air flow, generation of vortex) due to collision with the edge of the blade 20 can be reduced.

  As shown in the diagram on the right side of FIG. 8, air collides with the edge of the fan suction port 14 of the blade 20, and the air flow forms a vortex, thereby causing air separation. Increases as the air flow goes to the blade trailing edge 21, leading to an increase in fluid sound and a decrease in the discharge air volume due to the turbulence of the air flow. FIG. 9 shows a state where air separation occurs in the right side of FIG.

  On the other hand, by mitigating the collision with air on the surface 25 on the side edge of the fan suction port 14 of the blade 20, fluid noise caused by air separation can be reduced, and a smooth air flow is realized. be able to. Thereby, since the discharge air volume can be increased, the fan rotation speed can be reduced, and the fluid sound and the power consumption can be further reduced.

  Thus, since the turbulence caused by the separation of the air is suppressed in the air flow discharged by the turbo fan 1, the inconvenience that the turbulent air flow is blown out to the heat exchanger 6 can be reduced. By the inflow of a smooth air flow, the interference sound with the heat exchanger 6 can be reduced, and the generation of noise can be suppressed.

  In the present embodiment, the dimension of the first region P1 in the height direction of the blade 20 is configured to be larger than that of the second region P2. Specifically, as shown in FIG. 10, the height of the blade 20 in the first region P <b> 1 (the end portion on the side of the fan suction port 14) is closest to the ring portion 13 side of the joint portion between the blade 20 and the ring portion 13. It is set as the structure located in the fan inlet 14 side rather than the intermediate part of the edge part 16A and the junction part 17 of the blade | wing 20 and the main board part 12. FIG.

  Therefore, the area of the first region P1 that greatly affects the amount of air discharged by the rotation of each blade 20 can be secured larger than that of the second region P2, and thus the height at which air is discharged by the first region P1. Sufficient dimensions can be secured. Thereby, it is possible to secure a larger amount of air discharged in substantially the same direction.

  Accordingly, as in this embodiment, the rectified air can be discharged toward the fin-and-tube heat exchanger 6 disposed on the blow-out side of the turbofan 1, and the fluid caused by the interference of the fins Sound can be reduced.

  In addition, since the blade 20 in the present embodiment has a two-dimensional shape, it is possible to move and separate the two punching dies in the direction of the rotation axis at the time of molding, and it can be easily manufactured. Because this molding method can be adopted, unlike a three-dimensional wing with a complicated shape, it can be manufactured at a low cost and made lighter when it is made of the same dimensions and materials. Can do.

AC air conditioner P1 1st region P2 2nd region T3, T4 Maximum blade thickness V1 Portion located on main plate side V2 Portion located on fan inlet L1 Blade chord line on main plate side L2 Fan inlet Chord line on the side C1 center line on the main plate side C2 center line on the fan suction port side θ1 inlet angle on the main plate side θ2 inlet angle on the fan suction port side 1 turbo fan (centrifugal fan)
2 casing 3 conditioned room 4 air inlet 5 air outlet 6 heat exchanger 7 bell mouth 10 motor 12 main plate part 12A bulging part 13 ring part 14 fan inlet 15 fan outlet 16 joint part of blade and ring part 16A End 17 Joint between blade and main plate 20 Blade 21 Blade trailing edge 22 Blade leading edge 23 Surface on rotation side 24 Surface on counter rotation direction 25 Surface of fan suction port side edge of blade

Claims (6)

In a centrifugal fan having a main plate part, a ring part facing the main plate part, and a plurality of blades straddling between the main plate part and the outer peripheral part of the ring part, and having a fan suction port in the center part,
The blade has a two-dimensional shape, and a chord line of a portion located on the fan suction port side of the blade is offset to a rotation direction side from a chord line of a portion located on the main plate portion side. Centrifugal fan characterized by   An inlet angle, which is an angle formed by a chord line and a center line of a portion located on the fan suction port side of the blade, is smaller than the inlet angle of a portion located on the main plate side. The centrifugal fan according to claim 1. In a centrifugal fan having a main plate part, a ring part facing the main plate part, and a plurality of blades straddling between the main plate part and the outer peripheral part of the ring part, and having a fan suction port in the center part,
The blade has a two-dimensional shape, and an inlet angle that is an angle formed by a chord line and a center line of a portion located on the fan inlet side of the blade is in front of a portion located on the main plate portion side. Centrifugal fan characterized by being smaller than entry angle. In a centrifugal fan having a main plate part, a ring part facing the main plate part, and a plurality of blades straddling between the main plate part and the outer peripheral part of the ring part, and having a fan suction port in the center part,
The blade has a two-dimensional shape, and the portion of the blade located on the fan suction port side is tapered, and the surface on the counter-rotation direction side is inclined more slowly than the surface on the rotation direction side. Centrifugal fan characterized by being made. The blade comprises a first region that is a portion located on the main plate portion side and a second region that is a portion located on the fan suction port side,
The centrifugal fan according to any one of claims 1 to 4, wherein a dimension of the first region in the height direction of the blade is larger than that of the second region.   A centrifugal fan according to any one of claims 1 to 5, an air suction port that is formed corresponding to a fan suction port of the centrifugal fan, and sucks air from a conditioned room, and a blowout of the centrifugal fan An air conditioner comprising: a heat exchanger disposed on a side; and an air outlet through which air exchanged with the heat exchanger is blown into the room to be conditioned.

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