Axial flow fan and fan stator

Abstract

Provided are an axial-flow fan and a stator that produce effects including high efficiency and a flow-straightening effect by providing a proper configuration of the fan and an adjusted number of the blades and thereby preventing air flows from changing suddenly, in the axial-flow fan made of plastic and separately including an outer ring, a hub positioned at a center of the outer ring, and a plurality of blades between the outer ring and the hub. The axial-flow fan made of plastic and separately including an outer ring, a hub positioned at the center of the outer ring, and a plurality of blades between the outer ring and the hub is characterized in that each of the blades curves rearward from its base portion on the central support member to a middle part of the blade and further curves forward from the middle part to the outer ring, the blade is wide and an actual length thereof is long, and the blade is twisted at a desired inclination angle.

Description

Technical Field

[0001] The present invention relates generally to an engine cooling axial-flow fan, which is rotationally driven for cooling an automobile engine and the like (including applications for cooling an EV battery, motor, FCV stack, and auxiliary equipment; hereinafter simply referred to as "engine cooling fan"), and to a fan stator for fixing via an electric motor that drives the engine cooling fan.Background Art

[0002] Generally, engine cooling axial-flow fans that are rotationally driven are used in vehicles such as automobiles for cooling purposes. Such cooling fans are required to have a configuration that satisfies various requirements, such as low noise, high efficiency, compactness, and the ability to achieve favorable pressure and flow rate values. Hence, to meet these requirements, various configurations of the fans have been heretofore proposed. For example, there has been known an axial-flow fan having fan blades that radially extend from the outer circumstance of a cylindrical hub having a substantially T-shaped cross section, in which a curved surface on the leading-edge side of each blade is formed toward the root side of the blade from the side of the axial end surface (see Patent Literature 1). However, due to the increasing demand for electric vehicles (EVs), cooling fans driven by electric motors rather than by engine rotational power have been required recently.

[0003] In the case of a fan driven by the electric motor or other rotary driving means, the fan and a stator are necessary and the performance is affected by the configuration or structure of the fan and the stator. Thus, for the fan stator for fixing via an electric motor driving an engine cooling fan, for example, there has been known one having a structure where stays with an axially-flat-plate shape are radially arranged between a mount positioned at the center portion and an annular outlet bell (see Patent Literature 2).Citation ListPatent Literature

[0004] Patent Literature 1: JP 4994975 B2 Patent Literature 2: JP 2012-229693 A Summary of InventionTechnical Problem

[0005] However, the conventional engine cooling axial-flow fan and stator have problems as described below.

[0006] That is, for example, an engine cooling fan dedicated to an output of 500 W has a drawback that the distance for changing the airflows generated by the fan is short because of short fan blades, which causes pressure resistance on the surfaces of the fan blades, thereby resulting in a decrease in efficiency. Further, a stator dedicated to the engine cooling fan with the 500 W output has a drawback that, because its stays themselves have a similar sectional shape to the fan blades but the airflows at an outlet of the fan do not match the shape of stator vanes, the airflows generated by the fan are obstructed, thereby increasing the driving torque. In addition, an engine cooling fan dedicated to an output of 1 kW has a drawback that, because the fan typically has 11 blades, the airflows generated by the upstream and downstream blades interfere with airflows around the blades, and besides, the distance for deflecting the airflows is also short because of short blades, which causes pressure resistance on the blade surfaces, thereby resulting in a decrease in efficiency. Furthermore, a stator dedicated to the engine cooling fan with the 1 kW output has a drawback that, because of the stays having the axially-flat-plate shape, the airflow generated by the fan is obstructed, thereby increasing the driving torque.

[0007] The present invention has been made to solve the drawbacks of the conventional axial-flow fan and fan stator. And, the invention aims to provide an axial-flow fan and a fan stator that produce effects including high efficiency and a flow-straightening effect by providing a proper configuration of the fan and an adjusted number of the blades and thereby preventing air flows from changing suddenly, in the axial-flow fan made of plastic and separately including an outer ring, a hub positioned at a center of the outer ring, and a plurality of blades between the outer ring and the hub.Solution to Problem

[0008] The axial-flow fan (a motor-driven fan) made of plastic according to the present invention separately includes a circular outer ring, a hub having a circular central support member positioned at a center of the outer ring, and a plurality of blades arranged between the outer ring and the hub. The axial-flow fan is characterized in that each of the blades curves rearward from its base portion on the hub having the central support member to a middle part of the blade and further curves forward from the middle part to the outer ring, and the blade is wide and an actual length of the blade is long, and further the blade is twisted at a desired inclination angle.

[0009] In addition, the axial-flow fan is characterized in that the circular outer ring, the hub having the circular central support member, and the blades may be integrally formed.

[0010] Further, the fan stator for fixing the axial-flow fan (a motor-driven fan) according to the present invention includes stays radially arranged between a mount positioned at a center and an annular outlet bell. The fan stator is characterized in that the stays have a cross-sectional shape aligned with a vector (the airflow direction and flow volume from the fan toward the stay) at an outlet side of the fan and the stays are twisted at a desired inclination angle in the rotational direction of the fan.Advantageous Effects of Invention

[0011] When the axial-flow fan of the present invention is, for example, an engine cooling fan dedicated to an output of 500 W, it is possible to prevent a sudden change in air flows, thereby achieving high efficiency and the flow-straightening effect, owing to the configuration in which the axial-flow fan made of plastic separately includes the circular outer ring, the hub having the circular central support member positioned at the center of the outer ring, and a plurality of blades arranged between the outer ring and the hub, each of the blades curving rearward from its base portion on the hub having the central support member to the middle part of the blade and further curving forward from the middle part to the outer ring, and the blade being wide and the actual length of the blade being long, and further the blade being twisted at a desired inclination angle. Furthermore, when the axial-flow fan of the present invention is an engine cooling fan dedicated to an output of 1kW, it is possible to prevent interference between air flows and adjacent blades by reducing the number of the blades to achieve higher efficiency, in addition to the high efficiency due to control of the sudden change in air flows as is the case with the cooling fan dedicated to an output of 500 W. Besides, it is possible to achieve improvement in fan performance owing to the fan stator having the configuration that the stays have the cross-sectional shape aligned with a vector at the outlet side of the fan and the stays are twisted at a desired inclination angle in the rotational direction of the fan.Brief Description of Drawings

[0012] Fig. 1 is a perspective view showing an embodiment of an axial-flow fan (dedicated to 1kW output) according to the present invention. Fig. 2 is a perspective view showing an embodiment of a fan stator dedicated to the axial-flow fan shown in Fig. 1. Fig. 3 is a perspective view showing an embodiment of another axial-flow fan (dedicated to 500 W output) according to the present invention. Fig. 4 is a perspective view showing an embodiment of a fan stator dedicated to the axial-flow fan shown in Fig. 3. Fig. 5 is a view showing a comparative example of the conventional axial-flow fan (dedicated to 1kW output) having a specific shape (including dimensions). Fig. 6 is a view showing an embodiment of the axial-flow fan (dedicated to 1 kW output) having a specific shape (including dimensions) according to the present invention. Fig. 7 is a view showing a comparative example of the conventional stator (dedicated to 1kW output) having a specific shape (including dimensions). Fig. 8 is a view showing an embodiment of the stator (dedicated to 1 kW output) having a specific shape (including dimensions) according to the present invention. Fig. 9 is a comparative chart (P-Q performance) of ring fans with the output of 1 kW between the present invention and the conventional art at 3050 rpm (vertical axis: Static Pressure, horizontal axis: Air Flow). Fig. 10 is a comparative chart (L-Q performance) of the ring fans with the output of 1 kW between the present invention and the conventional art at 3050 rpm (vertical axis: Power, horizontal axis: Air Flow). Fig. 11 is a comparative chart (E-Q performance) of the ring fans with the output of 1 kW between the present invention and the conventional art at 3050 rpm (vertical axis: Static Pressure Efficiency, horizontal axis: Air Flow). Fig. 12 is a view showing a comparative example of the conventional axial-flow fan (dedicated to 500 W output) having a specific shape (including dimensions). Fig. 13 is a view showing an embodiment of the axial-flow fan (dedicated to 500 W output) having a specific shape (including dimensions) according to the present invention. Fig. 14 is a view showing a comparative example of the conventional stator (dedicated to 500 W output) having a specific shape (including dimensions). Fig. 15 is a view showing an embodiment of the stator (dedicated to 500 W output) having a specific shape (including dimensions) according to the present invention. Fig. 16 is a comparative chart (P-Q performance) of ring fans with the output of 500 W between the present invention and the conventional art at 4100 rpm (vertical axis: Static Pressure, horizontal axis: Air Flow). Fig. 17 is a comparative chart (L-Q performance) of the ring fans with the output of 500 W between the present invention and the conventional art at 4100 rpm (vertical axis: Power, horizontal axis: Air Flow). Fig. 18 is a comparative chart (E-Q performance) of the ring fans with the output of 500 W between the present invention and the conventional art at 4100 rpm (vertical axis: Static Pressure Efficiency, horizontal axis: Air Flow). Description of Embodiments

[0013] One embodiment of an axial-flow fan according to the present invention is described below.

[0014] An axial-flow fan 1 (dedicated to 1kW output) shown in Fig. 1 is composed of a circular outer ring 11, a hub 12 including a circular central support member positioned at the center of the outer ring, and a plurality of blades 13 arranged between the outer ring 11 and the hub 12. The features of the axial-flow fan lie in the configuration of the (nine) blades 13 disposed between the outer ring 11 and the hub 12. That is, the blades 13 of the axial-flow fan dedicated to 1kW output of the present invention each have such a configuration that the blade curves rearward from its base portion on the hub 12 having the central support member to the middle part of the blade and further curves forward from the middle part to the outer ring 11, and it is wide and has the actual length longer than the conventional product by approximately 1.3 to 1.5 times, and further it is integrally formed with the inner surface of the outer ring 11 and the outer surface of the hub 12 in such a manner that base portions of both ends of the blade 13 are twisted at a desired inclination angle. In this regard, the width, the length, and the inclination angle of the base portions of the ends of the blade 13 are not particularly limited but are set appropriately to control a sudden change in the flow of air or wind between the blades 13 according to the output of the axial-flow fan, thereby achieving higher efficiency.

[0015] Further, a stator 2 for the axial-flow fan dedicated to 1 kW output is, as shown in Fig. 2 as one embodiment, composed of a circular outer ring 21, a hub support 22 provided at its central portion, stays 23 arranged radially between the outer ring 21 and the hub support 22, and a reinforcing ring 24. A feature of the stator lies in that the stays 23 having a wing shape and arranged radially between the outer ring 21 and the hub support 22 are integrally formed with the inner surface of the outer ring 21 and the outer surface of the hub support 22 in such a manner that both ends of each stay 23 are twisted at a desired inclination angle. In this regard, the reason why the stays 23 are formed into the wing shape is to improve the fan performance.

[0016] In the configuration which employs the axial-flow fan 1 shown in Fig. 1 and the stator 2 for the axial-flow fan shown in Fig. 2, it is possible not only to ensure a desired air flow / volume since the blade 13 curves rearward from its base portion at the hub 12 having the central support member to the middle part of the blade and further curves forward from the middle part to the outer ring 11 and the actual length of the blade is longer than that of the conventional product by approximately 1.3 to 1.5 times, but also to suppress interference between air flows and adjacent blades due to an effect of reduction in the number of blades in addition to the configuration in which each blade 13 is integrally formed with the inner surface of the outer ring 11 and the outer surface of the hub 12 in such a manner that the base portions of both ends of the blade 13 are twisted at the desired inclination angle, thereby resulting in improved efficiency.

[0017] More details are shown on the configurations and dimensions (Tables 1 and 2) and experimental data (performance comparison) (Figs. 9 to 11) of the axial-flow fan dedicated to 1kW output (Fig. 6) and the stator for the axial-flow fan (Fig. 8) of the present invention as well as the conventional axial-flow fan dedicated to 1kW output (Fig. 5) and the conventional stator for the axial-flow fan (Fig. 7).

[0018] As is seen by experimental data, it is shown that the axial-flow fan dedicated to 1kW output and the stator for the axial-flow fan of the present invention resulted in a 7.2% increase in air flow, in a 15.0% increase in static pressure, in a 2.4% saving in power, and in a 10.8% improvement in static pressure efficiency.

[0019] An axial-flow fan 3 dedicated to 500 W output as shown in Fig. 3 and a stator 4 for the axial-flow fan as shown in Fig. 4 also have basically almost the same structure as the axial-flow fan 1 dedicated to 1 kW output as shown in Figs. 1 and 2 and the stator 2 shown in Fig. 2, respectively. Besides, they produce almost the same effects. That is, the axial-flow fan 3 dedicated to 500 W output as shown in Fig. 3 is composed of a circular outer ring 31, a hub 32 having a circular central support member positioned at the center of the outer ring, and a plurality of blades 33 arranged between the outer ring 31 and the hub 32. The axial-flow fan 3 is slightly different from the axial-flow fan 1 dedicated to 1kW output as shown in Fig. 1 in the numbers of the blades 33 arranged between the outer ring 31 and the hub 32 fewer than those of the axial-flow fan 1 and in the shape and twist angle of each blade 33. Obviously, the width, the length, and the inclination angle of the base portions of the ends of the blade 33 are not particularly limited but are set appropriately to control a sudden change in the flow of air or wind between the blades 33 according to the output of the axial-flow fan, thereby achieving higher efficiency. Furthermore, the width, the length, and the inclination angle of the base portions of the ends of the blade 33 are not particularly limited, as with the axial-flow fan 1 dedicated to 1 kW output, but are set appropriately to control a sudden change in the flow of air or wind between the blades 33 according to the output of the axial-flow fan, thereby achieving higher efficiency.

[0020] As described above, the stator 4 for the axial-flow fan dedicated to 500 W output shown in Fig. 4 also has almost the same structure as the stator 2 for the axial-flow fan dedicated to 1kW output as shown in Fig. 2. That is, the stator 2 is composed of a circular outer ring 41, a hub support 42 provided at its central portion, and stays 43 arranged radially between the outer ring 41 and the hub support 42. A feature of the stator lies in that the stays 43 having a wing shape and arranged radially between the outer ring 41 and the hub support 42 are integrally formed with the inner surface of the outer ring 41 and the outer surface of the hub support 42 in such a manner that both ends of each stay 43 are twisted at a desired inclination angle, as with the stator 2 for the axial-flow fan dedicated to 1kW output. In this regard, the reason why the stays 43 are formed into the wing shape is to improve the fan performance, as is the case with the axial-flow fan dedicated to 1kW output.

[0021] More details are shown on the configurations and dimensions (Tables 3 and 4) and experimental data (performance comparison) (Figs. 16 to 18) of the axial-flow fan dedicated to 500 W output (Fig. 13) and the stator for the axial-flow fan (Fig. 15) of the present invention as well as the conventional axial-flow fan dedicated to 500 W output (Fig. 12) and the conventional stator for the axial-flow fan (Fig. 14).

[0022] As is seen by experimental data, it is shown that the axial-flow fan dedicated to 500 W output and the stator for the axial-flow fan of the present invention resulted in a 6.5% increase in air flow, in a 13.3% increase in static pressure, and in a 6.9% improvement in static pressure efficiency, although power was increased by 4.7%. [Table 1]Difference in Configuration of 1000 W FanHeight of Cross sectionConventional ProductPresent Invention110Chord Length [mm]50.866.5Blade Angle [°]1619.6Maximum Camber [mm]4.33.1Center Position [mm]-5.71.5150Chord Length [mm]55.375.6Blade Angle [°]14.716.2Maximum Camber [mm]42.6Center Position [mm]-12.6-2.6200Chord Length [mm]61.1104.9Blade Angle [°]1411.6Maximum Camber [mm]6.63.1Center Position [mm]-0.339.4 [Table 2] Difference in Configuration of 1000 W StatorHeight of Cross sectionConventional ProductPresent Invention75Chord Length [mm]2731Blade Angle [°]9060.3Maximum Camber [mm]02.3Center Position [mm]0-0.1150Chord Length [mm]18.221.1Blade Angle [°]9059.1Maximum Camber [mm]01.9Center Position [mm]018.2 [Table 3] Difference in Configuration of 500 W FanHeight of Cross sectionConventional ProductPresent Invention80Chord Length [mm]52.260.6Blade Angle [°]28.725.3Maximum Camber [mm]5.66.8Center Position [mm]-8.40.5100Chord Length [mm]48.658.2Blade Angle [°]25.121.2Maximum Camber [mm]4.54.1Center Position [mm]-6.11.1140Chord Length [mm]64.167.6Blade Angle [°]11.410.4Maximum Camber [mm]4.26.4Center Position [mm]9.516.7 [Table 4] Difference in Configuration of 500 W StatorHeight of Cross sectionConventional ProductPresent Invention75Chord Length [mm]25.430.5Blade Angle [°]54.943.1Maximum Camber [mm]3.14.1Center Position [mm]7.96.5150Chord Length [mm]19.928.4Blade Angle [°]65.841.4Maximum Camber [mm]1.74.2Center Position [mm]4.75.9 [Table 5] 1000 W: Performance ComparisonComparison at 3050 rpm, k=0.063Conventional ProductPresent InventionAir Flow [m 3< / min]71.476.5 (+7.2%)Static Pressure [kPa]0.320.37 (+15.0%)Power [kW]0.940.92 (-2.4%)Static Pressure Efficiency [%]41.252.0 (+10.8%) [Table 6] 500W: Performance ComparisonComparison at 4100 rpm, k=0.5Conventional ProductPresent InventionAir Flow [m 3< / min]29.231.1 (+6.5%)Static Pressure [kPa]0.4250.482 (+13.3%)Power [kW]0.460.48 (+4.7%)Static Pressure Efficiency [%]45.352.2 (+6.9%) Reference signs

[0023] 1Axial-flow fan dedicated to 1 kW output 2Stator for axial-flow fan dedicated to 1kW output 3Axial-flow fan dedicated to 500 W output 4Stator for axial-flow fan dedicated to 500 W output 11, 21, 31, 41Outer ring 12, 32Hub 13, 33Fan blade 22, 42Hub support 23, 43Stay 24Reinforcing ring

Claims

1. An axial-flow fan made of plastic, separately comprising a circular outer ring, a hub having a circular central support member positioned at a center of the outer ring, and a plurality of blades arranged between the outer ring and the hub, wherein each of the blades curves rearward from its base portion on the central support member to a middle part of the blade and further curves forward from the middle part to the outer ring, the blade is wide and an actual length thereof is long, and the blade is twisted at a desired inclination angle.

2. The axial-flow fan according to claim 1, wherein the circular outer ring, the hub having the circular central support member, and the blades are integrally formed.

3. A fan stator of fixing an axial-flow fan, comprising stays radially arranged between a mount positioned at a center and an annular outlet bell, wherein the stays have a cross-sectional shape aligned with a vector at an outlet side of the fan and are twisted at a desired inclination angle in a rotational direction of the fan.

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