HK1200897B - Propeller fan - Google Patents

Description

Propeller fan

The present application is a divisional application of an invention patent application entitled "propeller fan", having an international application date of 2009/4/28, an international application number of PCT/JP2009/058369, and a national application number of 200980157715.5.

Technical Field

The present invention relates to a propeller fan used for a ventilation fan, an air conditioner, and the like.

Background

Conventionally, there has been disclosed a propeller fan in which a plurality of blades are provided on an outer peripheral portion of a hub attached to a rotating shaft, and in a cylindrical cross section of the blades cut along an arbitrary radius from the rotating shaft, a position where a maximum amount of warpage is located on a trailing edge side of the blades as the radius increases (see, for example, patent document 1).

Further, there is disclosed an axial flow fan including a hub rotating by receiving a driving force and blades connected to a periphery of the hub, wherein the blades are thin blades and have a warp, a maximum camber (camber) of the warp is set in a range of 5% to 8% of a blade chord length, and a maximum camber position is set in a range of 20% to 40% of the blade chord length (for example, see patent document 2).

Patent document 1: japanese patent No. 3608038

Patent document 2: japanese laid-open patent publication No. 2-233899

However, according to the above-described conventional technique, a large blade outer edge vortex is generated at the blade outer edge. Therefore, there is a problem that the air-noise characteristics are deteriorated.

Disclosure of Invention

The present invention has been made in view of the above problems, and an object of the present invention is to provide a propeller fan in which blade outer edge vortices generated at the outer edges of blades of the propeller fan are suppressed and blowing-noise characteristics are improved.

In order to solve the above problems and achieve the object of the present invention, a propeller fan of the present invention includes: a boss fitted to the rotary shaft; and a plurality of blades radially provided on the hub and blowing air in a direction of a rotation axis, wherein in a 1 st region of the blades from the rotation axis to a predetermined radius, a maximum camber line in a cylindrical cross section of the blades cut along an arbitrary radius from the rotation axis is located within 50% of a blade chord length from a blade leading edge, and in a 2 nd region of the blades from the predetermined radius to a blade outer edge, a maximum camber line in a cylindrical cross section of the blades cut along an arbitrary radius from the rotation axis is connected to the maximum camber line in the 1 st region at the predetermined radius position, located on a blade trailing edge side with an increase in radius, and located within 50% of the blade chord length from the blade leading edge at the blade outer edge.

The propeller fan of the present invention has the effect of suppressing the blade outer edge vortex generated at the blade outer edge and improving the air supply-noise characteristics.

Drawings

Fig. 1 is a perspective view showing a general propeller fan.

Fig. 2-1 is a plan view of a propeller fan according to embodiment 1 of the present invention.

Fig. 2-2 is a cylindrical cross-sectional view of the blade of embodiment 1 in the 1 st region.

Fig. 3-1 is a perspective view schematically showing the airflow on the negative pressure surface side of the blade according to embodiment 1.

Fig. 3-2 is a sectional view taken along line F-F in fig. 3-1.

Fig. 4-1 is a view showing an air flow around a blade having the conventional camber CLD blade shown in fig. 2-2.

Fig. 4-2 is a view showing the air flow around the blades of the blade having the camber CLD' of embodiment 1 in fig. 2-2.

Fig. 5 is a graph showing the specific noise characteristics of the blade having the maximum camber edge line CL' of embodiment 1 shown in fig. 2-1, and the specific noise characteristics of the blade having the conventional maximum camber edge line CL in comparison with each other.

Fig. 6 is a perspective view showing a propeller fan having blades according to embodiment 2, in which the blades according to embodiment 2 are formed in a wave shape on the leading edge side of the inner peripheral portion of the blade having the maximum camber line CL' according to embodiment 1.

Fig. 7 is a perspective view schematically showing an air flow on the negative pressure surface side of the blade of embodiment 2 shown in fig. 6.

Fig. 8 is a perspective view showing a propeller fan having blades according to embodiment 3, in which the blades according to embodiment 3 are formed in a wave shape on the trailing edge side of the inner peripheral portion of the blade having the maximum camber line CL' according to embodiment 1.

Fig. 9 is a perspective view schematically showing an air flow on the negative pressure surface side of the blade of embodiment 3 shown in fig. 8.

Fig. 10 is a graph showing the specific noise of the blade shown in fig. 6 and 8.

Fig. 11 is a perspective view showing a propeller fan having blades curved toward the upstream side of the air flow in the blade outer peripheral side.

Fig. 12 is a perspective view schematically showing an air flow on the negative pressure surface side of the blade shown in fig. 11.

Fig. 13 is a plan view of the propeller fan shown in fig. 1 projected on a plane orthogonal to the rotation axis.

Fig. 14 is a view of rotationally projecting the locus of the chord center point Pr of each blade in fig. 13 at a radius R onto a vertical plane containing the rotation axis and the OX axis.

Fig. 15 is a diagram showing a blade chord center line Pr1 of a blade in which the blade outer peripheral side is curved toward the upstream side of the air flow.

Fig. 16 is a view similar to fig. 15 showing a method of defining a blade chord center line Pr1 of a blade in which the blade outer peripheral side is curved toward the upstream side of the air flow.

Fig. 17 is a view schematically showing the air flow on the negative pressure surface side of a blade in which the outer peripheral side of the blade is curved toward the upstream side of the air flow, wherein the blade has a ridge line CL' of the camber in embodiment 1 shown in fig. 2-1.

Fig. 18 is a diagram showing the specific noise of the propeller fan according to embodiment 4 of the present invention.

Fig. 19 is a diagram showing fan efficiency of the propeller fan according to embodiment 4.

Detailed Description

Hereinafter, embodiments of the propeller fan according to the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the embodiment.

Embodiment mode 1

Fig. 1 is a perspective view showing a general propeller fan, fig. 2-1 is a plan view of a propeller fan according to embodiment 1 of the present invention, and fig. 2-2 is a cylindrical sectional view of a 1 st region of a blade according to embodiment 1.

The propeller fan shown in fig. 1 has 3 blades, but the number of blades is not limited in the present invention, and may be other numbers. In the following description, the shape of 1 blade will be mainly described, and the shapes of the other blades are the same.

As shown in fig. 1, blades 1 having a three-dimensional shape are radially attached to an outer peripheral portion of a cylindrical boss 2, and the boss 2 is rotated in a direction of a rotation direction B around a rotation shaft 3 by being rotationally driven by a motor, not shown. Further, the boss 2 is cylindrical, but the blades 1 may be formed radially on the outer peripheral portion of the boss formed by bending a metal plate. By the rotation of the blade 1, an air flow in the air flow direction a is generated. The upstream surface of the vane 1 serves as a negative pressure surface, and the downstream surface serves as a positive pressure surface.

When the blade 1 shown in fig. 1 is projected on a plane orthogonal to the rotation axis 3, the blade 1 shown in fig. 2-1 has a shape. A broken line CL shown in fig. 2-1 is a conventional maximum camber ridge line (a locus of a vertex of a camber) of the blade 1, and is located at the center of the blade leading edge 1b and the blade trailing edge 1c of the blade 1. The camber of the blade 1 has an arc shape such as a broken line CLD (conventional camber) shown in fig. 2-2 in any cylindrical cross section having a radius R1.

In the blade 1 according to embodiment 1, the maximum camber edge line CL ' is located at CL1 ' on the inner circumferential side of the radius R2 and at CL2 ' on the outer circumferential side of the radius R2, with a predetermined radius R2 as a boundary. That is, on the inner peripheral side of the radius R2, the maximum camber ridge line CL1 'is located closer to the blade leading edge 1b than the conventional maximum camber ridge line CL located at the center of the blade leading edge 1b and the blade trailing edge 1c of the blade 1, and has a non-circular-arc shape like a solid line CLD' (camber of embodiment 1) shown in fig. 2-2.

Fig. 3-1 is a perspective view schematically showing the airflow on the negative pressure surface side of the blade according to embodiment 1, and fig. 3-2 is a cross-sectional view taken along line F-F in fig. 3-1. When the blade 1 rotates in the direction of the rotation direction B, air flows in the direction a of the airflow. A pressure difference is generated between the negative pressure surface 1f and the positive pressure surface 1G of the blade 1, and as shown in fig. 3-2, a leakage airflow and a blade outer edge vortex G are generated from the positive pressure surface 1G side toward the negative pressure surface 1f side at the blade outer edge 1 d. On the other hand, an inner peripheral blade airflow E is generated on the inner peripheral side of the blade substantially along the suction surface 1 f. As described above, the airflow on the negative pressure surface 1f side of the propeller fan 91 according to embodiment 1 is roughly divided into two types of airflows having different shapes, i.e., the blade outer periphery airflow D and the blade inner periphery airflow E.

Fig. 4-1 is a view showing an air flow around a blade having a blade with a conventional camber CLD in fig. 2-2, and fig. 4-2 is a view showing an air flow around a blade having a camber CLD' of embodiment 1 in fig. 2-2.

As shown in fig. 4-1, when the blade 1 rotates in the rotation direction B, an airflow from the blade leading edge 1B toward the blade trailing edge 1c is generated. The negative pressure surface air flow H of the conventional camber CLD having the maximum camber ridge line CL becomes unstable as it approaches the blade trailing edge 1c, and generates a vortex, and merges with the pressure surface air flow at the blade trailing edge 1c to generate a large blade trailing edge vortex J. Due to such a vortex in the negative pressure surface air flow H and the blade trailing edge vortex J, noise is generated.

On the other hand, as shown in fig. 4-2, in the suction surface air flow H 'of the camber line CLD' of embodiment 1 having the maximum camber ridge line CL ', the air flowing in from the blade leading edge 1b flows along the suction surface 1f as compared with the conventional camber line CLD, the generation of the vortex is suppressed, the scale of the blade trailing edge vortex J' generated at the blade trailing edge 1c is also reduced, and the noise is reduced as compared with the blade having the conventional camber line CLD.

As described above, the blades 1 are formed in the shape of the camber height CLD ', which reduces turbulence of the suction surface airflow H' and noise, but as shown in fig. 3-1, in the propeller fan 91, a large blade outer edge vortex G is generated in the blade outer peripheral airflow D, and therefore, the flow state is greatly different from that of the blade inner peripheral airflow E. Therefore, if the camber of the blade outer peripheral portion is formed to be the same as the camber CLD', the blade outer edge vortex G is greatly changed, and the air-flow-noise characteristics may be deteriorated.

Therefore, in the propeller fan 91 according to embodiment 1, as shown in fig. 2-1, the maximum camber edge line CL 'of the blade 1 is formed into edge lines having different shapes, such as CL 1' and CL2 ', the maximum camber edge line CL 1' is located within 50% of the blade chord length from the blade leading edge 1b, and the maximum camber edge line CL2 'at the blade outer peripheral portion is located on the blade trailing edge 1c side as the radius increases from the position connected to the maximum camber edge line CL 1', and is located within 50% of the blade chord length at the blade outer edge 1 d. Reference numeral CLt in fig. 2-1 denotes the maximum camber position of the outer edge of the blade, CLb denotes the maximum camber position of the inner edge of the conventional blade, and CLb' denotes the maximum camber position of the inner edge of the blade in embodiment 1.

Fig. 5 is a graph showing the specific noise characteristics of the blade having the maximum camber edge line CL' of embodiment 1 shown in fig. 2-1, and the specific noise characteristics of the blade having the conventional maximum camber edge line CL in comparison with each other. The maximum camber line CL' of embodiment 1 shown in fig. 5 is located at a position 35% of the blade chord length from the blade leading edge 1b in the 1 st region from the blade inner edge 1e to the blade radius R2 of 0.675 × Rt (Rt is the blade outer edge radius), is located at a position 35% of the blade chord length from the blade leading edge 1b in the 2 nd region from R2 to the blade outer edge 1d, is located at a position closer to the blade trailing edge 1c as the radius increases, and is located at a position 50% of the blade chord length at the blade outer edge 1 d. In the conventional blade for comparison, the maximum camber line CL is located at a position 50% of the blade chord length from the blade leading edge 1 b.

In addition, specific noise K_TIs defined by the following formula.

K_T＝SPL_A-10Log(Q·P_T ^2.5)

Q: air volume [ m ]³/min]

P_T: bulk pressure [ Pa]

SPL_A: noise characteristics (after A correction) [ dB]

In fig. 5, the vertical axis represents the specific noise, the 1 scale indicated by the broken line represents the difference of 1dBA, and the horizontal axis represents the air volume. As shown in fig. 5, the noise of the blade having the maximum camber line CL' of embodiment 1 can be reduced to about-1 dBA at the maximum.

Embodiment mode 2

Fig. 6 is a perspective view showing a propeller fan 92 having blades 21 according to embodiment 2, in which the blades 21 according to embodiment 2 are formed in a wave shape 21m on the leading edge side of the inner peripheral portion of the blade having the maximum camber line CL' according to embodiment 1. The waveform of the blade leading edge 21b becomes the maximum waveform and gradually becomes the small waveform toward the blade center portion.

Fig. 7 is a perspective view schematically showing the airflow on the negative pressure surface side of the blade 21 of embodiment 2 shown in fig. 6. As shown in fig. 7, in the air flowing into the blade leading edge 21b, a longitudinal vortex is generated by the waveform 21m of the blade 21, and the blade inner peripheral airflow E becomes an airflow E2 with less disturbance, so that noise caused by disturbance of the airflow can be reduced.

Embodiment 3

Fig. 8 is a perspective view showing a propeller fan 93 having the blade 31 according to embodiment 3, and the blade 31 according to embodiment 3 is formed in a waveform 31m on the blade inner peripheral portion rear edge side of the blade having the maximum camber line CL' according to embodiment 1. The waveform of the blade trailing edge 31c is the maximum waveform and gradually becomes a small waveform toward the blade center portion.

Fig. 9 is a perspective view schematically showing the airflow on the negative pressure surface side of the blade 31 of embodiment 3 shown in fig. 8. As shown in fig. 9, the vertical vortex generated by the waveform 31n of the blade 31 reduces the turbulence of the air caused by the vortex generated at the trailing edge 31c of the blade, and the airflow E3 with less turbulence is generated, thereby reducing the noise caused by the turbulence of the airflow.

Fig. 10 is a graph showing the specific noise of the blades 21 and 31 shown in fig. 6 and 8. As shown in FIG. 10, in the region of large air volume, the noise of the blades 21, 31 formed in a waveform on the inner peripheral side of the blades can be reduced to about-0.5 [ dBA ] at the maximum.

Embodiment 4

Fig. 11 is a perspective view showing a propeller fan having blades curved toward the upstream side of the air flow on the outer peripheral side of the blades, and fig. 12 is a perspective view schematically showing the air flow on the negative pressure surface side of the blades shown in fig. 11. The propeller fan having the blades in which the blade outer peripheral sides are curved toward the upstream side of the airflow shown in fig. 11 and 12 can reduce the noise due to the blade outer edge vortex by attenuating the blade outer edge vortex generated at the blade outer edge negative pressure surface, but the blade outer peripheral sides are curved toward the upstream side of the airflow, so that a part of the pressure increase component generated by the rotation of the blades leaks to the negative pressure surface side, and the fan efficiency is slightly lowered.

The noise source of the blade shown in fig. 1 and 11 includes: the noise caused by the vortex at the outer edge of the blade generated at the outer edge of the blade; noise caused by turbulence of airflow on the negative pressure surface of the blade; blade trailing edge vortices cause noise. In the blade in which the blade outer peripheral side is curved toward the upstream side of the air flow, the proportion of noise caused by the blade outer edge vortex becomes small, and the proportion of noise caused by the blade inner peripheral air flow becomes large. Therefore, it is necessary to improve the flow in the inner periphery of the blade and study the shape of the blade that does not affect the flow in the outer periphery of the blade.

In the blade in which the outer peripheral side of the blade is curved toward the upstream side of the air flow, by forming the maximum camber line CL' as shown in fig. 2-1, it is possible to reduce the noise due to the vortex at the outer edge of the blade without affecting the outer peripheral air flow, improve the inner peripheral air flow of the blade, further reduce the noise, and improve the fan efficiency.

Fig. 13 is a plan view of the propeller fan shown in fig. 1 projected on a plane orthogonal to the rotation axis, fig. 14 is a view of projecting the locus of each blade chord center point Pr in fig. 13 on a vertical plane including the rotation axis and the OX axis while rotating at a radius R, fig. 15 is a view showing the blade chord center line Pr1 of the blade curved toward the upstream side of the air flow on the blade outer periphery side, and fig. 16 is a view similar to fig. 15 showing the method of defining the blade chord center line Pr1 of the blade curved toward the upstream side of the air flow on the blade outer periphery side.

The definition of the shape of the vane in which the outer peripheral side of the vane is curved toward the upstream side of the air flow will be described with reference to fig. 13 to 16. When the blade 1 shown in fig. 1 is projected onto a plane Sc (see fig. 14) orthogonal to the rotation axis 3, the blade 1 shown in fig. 13 has a shape. A point Pb shown in fig. 13 indicates a blade chord center point (midpoint) from the blade leading edge 1b to the blade trailing edge 1c on the outer periphery of the hub 2.

Likewise, Pt denotes a blade chord center point (midpoint) from the blade leading edge 1b to the blade trailing edge 1c on the blade outer edge 1 d. A line Pr shown in fig. 13 indicates a locus (blade chord center line) of each blade chord center point at an arbitrary radius R from a blade chord center point Pb on the hub to a blade chord center point Pt on the outer edge of the blade.

Fig. 14 is a diagram showing a locus (blade chord center line) of each blade chord center point from the blade chord center point Pb of the hub to the blade chord center point Pt of the blade outer edge in fig. 13, that is, a locus (blade chord center line) of each blade chord center point Pr projected by rotating each blade chord center point Pr at an arbitrary radius R at a radius R onto a vertical plane including the rotation axis 3 and the OX axis with respect to the blade chord center point Pb-Pr-Pt.

As shown in fig. 14, a forward inclination angle z inclined toward the upstream side of the gas flow from the blade chord center point Pb of the hub 2 to the blade chord center point Pt of the blade outer edge of the blade, which is rotationally projected onto a vertical plane including the rotation axis 3 and the OX axis (trajectory of each blade chord center point Pr), can be represented by a line forming a certain angle with a plane Sc orthogonal to the rotation axis 3.

A blade chord center line Pr indicated by a broken line in fig. 15 is a locus of a blade chord center point of the blade 1 shown in fig. 14 and having a constant rake angle z, and a blade chord center line Pr1 is a locus of a blade chord center point of a blade having a blade outer peripheral portion curved to the upstream side of the airflow, and is located in a region between the blade chord center line Pr when the rake angle is constant and an OX axis (rake angle 0 °) passing through the blade chord center point Pb of the hub and perpendicular to the rotating shaft 3 in a region from the blade chord center point Pb of the hub to the blade chord center point Pt of the blade outer edge.

The blade chord center point Pb of the hub of the blade chord center line Pr1 and the blade chord center point Pt of the outer edge of the blade are located at the same position, and the distance from the blade chord center point Pt of the outer edge of the blade to the plane Sc is H.

Fig. 16 shows the locus and rake angle of each blade chord center point Pr2 of the blade of embodiment 4 in which the blade outer peripheral portion is curved toward the upstream side of the airflow a. The blade chord center point at an arbitrary radius R from the rotation axis 3 is Pr2, and the distance from the blade chord center point Pr2 on the blade chord center line Pr1 to the plane Sc perpendicular to the rotation axis 3 is Ls.

In the blade 41 of embodiment 4 shown in fig. 16, a 1 st region from the boss 2 (radius Rb) to a bending point Pw of a radial intermediate portion is inclined toward the upstream side at a constant 1 st rake angle zw, and a 2 nd region from the bending point Pw to the outer edge of the blade is inclined toward the upstream side of the 1 st region.

The radius of the curve point Pw on the blade chord center line Pr1 is Rw, and the 2 nd rake angle that is the inclination angle on the upstream side of the line Pr connecting the blade chord center point Pt on the blade outer edge and the blade chord center point Pb on the outer periphery of the hub 2 is zt. The 1 st rake angle zw is represented by the following formula.

zw＝tan^-1(Ls/(R-Rb))

(Rb＜R≤Rw)

As shown below, the inclination angle zd corresponding to the blade chord center point Pr2 at an arbitrary radius R in the 2 nd region from the bending point Pw to the blade outer edge (radius Rt) is formed as an n-th function (1. ltoreq. n) of the radius R.

zd＝α(R-Rb)ⁿ+zw

α＝(zt-zw)/(Rt-Rw)ⁿ

(Rw＜R≤Rt)

Instead of making the above-described inclination angle zd an nth function (1. ltoreq.n) of the radius R, the blade chord center line Pr1 in the 2 nd region may be linearly inclined toward the upstream side at a constant rake angle.

Fig. 17 is a view schematically showing the air flow on the negative pressure surface side of the vane 41 in which the vane outer peripheral portion is curved toward the upstream side of the air flow, and the vane 41 has a ridge line CL' of the maximum camber in embodiment 1 shown in fig. 2-1. As shown in fig. 17, according to the blade 41 of embodiment 4, the blade outer peripheral airflow and the blade inner peripheral airflow can be improved at the same time, and the air-noise characteristics can be improved.

Fig. 18 is a graph showing the specific noise of the propeller fan according to embodiment 4 of the present invention, and fig. 19 is a graph showing the fan efficiency of the propeller fan according to embodiment 4. In the blade 41 of the propeller fan according to embodiment 4, the maximum camber line CL 'is located at a position 35% of the blade chord length from the blade leading edge in the 1 st region from the blade inner edge R of 0.675 × Rt, and the maximum camber line CL' is arranged at a position 35% of the blade chord length from the blade outer edge at a position 50% of the blade chord length from the blade outer edge in the 2 nd region from R of 0.675 × Rt to the blade outer edge.

In addition, in the blade having the conventional maximum camber line CL for comparison, the maximum camber line CL is located at a position 50% of the blade chord length from the blade leading edge, the radius of the bending point Rw is 0.7 × Rt, the inclination angle zd corresponding to the blade chord center point Pr2 at an arbitrary radius R in the 2 nd region from the bending point Pw to the blade outer edge (radius Rt) is determined by the 2 nd-order function of the radius R, the inclination angle zs of the tangent 15 to the blade chord center line Pr1 at the blade chord center point Pt of the blade outer edge is 45 ° (see fig. 16), and fig. 18 shows the air volume Q and the specific noise K obtained by the experiment and shows that the inclination angle zs is 45 ° (see fig. 16)_TFIG. 19 shows the air quantity Q and the fan efficiency E obtained by the experiment_TThe result of the relationship of (1).

As shown in fig. 17 and 18, the propeller fan 94 according to embodiment 4 has a specific noise K within a practical range, as compared with a conventional propeller fan in which the blade outer peripheral portion is curved toward the upstream side of the airflow_TIs reduced (-1dBA), and the fan efficiency E_TThe improvement is obtained (about +2 to 3 points at the maximum).

In addition, the fan efficiency E_TIs defined by the following formula.

E_T＝(P_T·Q)/(60·P_W)

Q: air volume [ m ]³/min]

P_T: bulk pressure [ Pa]

P_W: shaft power [ W ]]

Industrial applicability of the invention

As described above, the propeller fan of the present invention is suitable for use in a ventilation fan, an air conditioner, and the like.

Description of the reference numerals

1. 21, 31, 41 blade

1b, 21b blade leading edge

1c, 31c blade trailing edge

1d outer edge of blade

1e blade inner edge

1f negative pressure surface

1g of positive pressure noodles

21m, 31n waveform

2 axle hub

3 rotating shaft

A direction of air flow

Direction of rotation B

Radius of any R1 blade in region 1

Boundary radius of No. 1 region and No. 2 region of R2 blade

CL maximum camber ridge of past blade

Maximum camber ridge of CL' embodiment 1 blade

Camber of CLD past blade

Camber of a leaf of CLD' embodiment 1

Maximum camber ridge of the 1 st region of the blade according to embodiment 1 of CL1

Maximum camber ridge of region 2 of the blade according to embodiment 1 of CL2

CLt maximum camber position of blade outer edge

Maximum camber position of blade inner edge of CLb conventional blade

Maximum camber position of blade inner edge of CLb' embodiment 1 blade

D blade peripheral air flow

E blade inner peripheral air flow

E2, E3 airflow

G blade outer edge vortex

H previous blade negative pressure surface air flow

Negative pressure surface flow of blade of embodiment 1

Blade trailing edge vortex of J past blade

Blade trailing edge vortex of blade of J' embodiment 1

91. 92, 93, 94 propeller fans.

Claims (3)

1. A propeller fan, comprising: a boss fitted to the rotary shaft; a plurality of blades radially provided on the hub and blowing air in a direction of the rotation axis,

the blade is divided into a 1 st area and a 2 nd area, the 1 st area is arranged on the rotating shaft side, the 2 nd area is arranged on the outer edge side of the blade and is connected with the 1 st area,

in the 1 st region, the maximum camber line in the cylindrical cross section of the blade cut along an arbitrary radius from the rotation axis is located within 50% of the blade chord length from the blade leading edge,

in the 2 nd region, a maximum camber line in a cylindrical cross section of the blade cut along an arbitrary radius from the rotation axis is connected to the maximum camber line in the 1 st region at a boundary between the 1 st region and the 2 nd region, is positioned on a blade trailing edge side with an increase in radius, and is positioned on a blade outer edge within 50% of a blade chord length from a blade leading edge.

2. Propeller fan according to claim 1,

the blade inner periphery leading edge side or the blade inner periphery trailing edge side is formed in a wave shape.

3. Propeller fan according to claim 1,

the outer peripheral side of the blade is curved toward the upstream side of the air flow.