Propeller fan

Abstract

To provide a propeller fan which is not displaced even if a worker erroneously applies a force in a radial direction to the propeller fan when a plurality of propeller fans are stacked.SOLUTION: The hub 10 includes an outer wall portion 11, an inner wall portion 12, a boss 15 to which a rotation shaft is attached, and an annular portion 13 which is annularly formed along the circumferential direction CD and in which a plurality of protruding portions 13b protruding in a direction away from the blade 20 from a predetermined position are disposed at intervals in the circumferential direction CD. And a plurality of position regulating portions 14 that are formed so as to protrude from each of a plurality of regions of the annular portion 13 disposed between the plurality of protruding portions 13b in the circumferential direction CD, are disposed on an inner side in the radial direction with respect to the outer wall portion 11, and regulate a position in the radial direction of the outer wall portion 11 of another propeller fan to be stacked.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to a propeller fan. [Background technology]

[0002] Conventionally, an axial fan has been known that includes a hub and a plurality of blades attached at intervals to the outer peripheral surface of the hub (see, for example, Patent Document 1). The axial fan disclosed in Patent Document 1 has a plurality of protrusions on the hub to reinforce the hub and prevent damage to the hub due to loads that pull the hub radially outward from the blades as the axial fan rotates. The axial fan disclosed in Patent Document 1 also has walls that extend circumferentially on the protrusions, thereby improving the strength of the hub against circumferential loads. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-112051 Summary of the Invention [Problem to be solved by the invention]

[0004] The axial fan of Patent Document 1 has a protrusion formed on one end face in the direction of the rotation axis and a recess formed on the other end face. Therefore, when multiple axial fans are stacked, the protrusion of one axial fan fits into the recess of the other axial fan, among the axial fans lined up in the stacking direction. This makes it possible to minimize the height in the stacking direction when multiple axial fans are stacked. It also makes it possible to prevent circumferential misalignment of the axial fans lined up in the stacking direction.

[0005] However, when the axial fans of Patent Document 1 are stacked, it is not possible to prevent radial displacement of the axial fans lined up in the stacking direction. If an operator accidentally applies radial force to an axial fan when stacking multiple axial fans, the axial fan stacked on top may shift from the position of the axial fan below and fall.

[0006] The present disclosure has been made in consideration of these circumstances, and aims to provide a propeller fan that will not shift out of position even if an operator accidentally applies radial force to a propeller fan when stacking multiple propeller fans. [Means for solving the problem]

[0007] In order to solve the above problems, the propeller fan of the present disclosure employs the following measures. a boss that is positioned radially inward of the inner wall portion and to which a rotating shaft that rotates around the axis is attached; an annular portion that is formed in a ring shape along the circumferential direction in a region sandwiched between the outer wall portion and the inner wall portion in the radial direction, and that has a plurality of protrusions that are spaced apart in the circumferential direction, with their tips along the axis protruding in a direction away from the blades beyond a predetermined position; and a plurality of position regulating portions that are formed to protrude from each of a plurality of regions of the annular portion that are positioned between the plurality of protrusions in the circumferential direction, and that are positioned radially inward of the outer wall portion and that regulate the radial position of the outer wall portions of other stacked propeller fans. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide a propeller fan that will not become misaligned even if a worker accidentally applies a radial force to a propeller fan when stacking multiple propeller fans. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a plan view showing a propeller fan according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a front view of the propeller fan shown in FIG. [Figure 3] FIG. 2 is a bottom view of the propeller fan shown in FIG. [Figure 4] 2 is a cross-sectional view of the propeller fan shown in FIG. 1 taken along the line AA. [Figure 5] FIG. 2 is a front view showing a state in which a plurality of propeller fans are stacked. [Figure 6] 6 is a cross-sectional view of the propeller fan shown in FIG. 5 taken along the arrow BB. [Figure 7] FIG. 3 is a development view of the propeller fan shown in FIG. 2 developed along the circumferential direction. [Figure 8] FIG. 10 is a development view of the annular portion of the first modified example developed in the circumferential direction. [Figure 9] FIG. 10 is a development view of the annular portion of the second modified example developed in the circumferential direction. DETAILED DESCRIPTION OF THE INVENTION

[0010] A propeller fan 100 according to an embodiment of the present disclosure will now be described with reference to the drawings. Fig. 1 is a plan view showing the propeller fan 100 according to an embodiment of the present disclosure. Fig. 2 is a front view of the propeller fan 100 shown in Fig. 1. Fig. 3 is a bottom view of the propeller fan 100 shown in Fig. 1. Fig. 4 is a cross-sectional view of the propeller fan 100 shown in Fig. 1, taken along the line AA. Blades 20 are not shown in Fig. 4.

[0011] Propeller fan 100 is installed, for example, in the outdoor unit of an air conditioning system, and is a device that rotates in a rotation direction ROD about an axis X by a fan motor (not shown). As shown in FIG. 1, propeller fan 100 includes a hub 10 and a plurality of blades 20. Propeller fan 100 is integrally formed from, for example, a resin material.

[0012] As shown in Figures 1 to 4, the hub 10 is a member that rotates around an axis X, and has an outer wall portion 11, an inner wall portion 12, an annular portion 13, a position control portion 14, a boss 15, and a connecting rib 16.

[0013] The outer wall portion 11 is a member formed in a cylindrical shape so as to surround the axis X. As shown in Fig. 1, an outer peripheral surface 11a of the outer wall portion 11 is formed in a circular shape centered on the axis X. As shown in Fig. 3, an inner peripheral surface 11b of the outer wall portion 11 is formed in a circular shape centered on the axis X.

[0014] The inner wall portion 12 is a member formed in a cylindrical shape so as to surround the axis X, and is disposed radially inward relative to the outer wall portion 11 in a direction perpendicular to the axis X.

[0015] The annular portion 13 is a member formed in an annular shape along the circumferential direction CD in a region sandwiched in the radial direction between the outer wall portion 11 and the inner wall portion 12. The annular portion 13 has a flat portion 13a and a protruding portion 13b.

[0016] As shown in FIG. 4, the flat portion 13a is a member that is arranged on a plane perpendicular to the axis X and is formed in a circular ring shape by connecting one end 11c of the outer wall portion 11 along the axis X and one end 12a of the inner wall portion 12 along the axis X.

[0017] 1 to 4, the protrusions 13b are arranged at a plurality of locations (three locations in the example shown in FIG. 1) spaced apart in the circumferential direction CD in a region sandwiched between the outer wall portion 11 and the inner wall portion 12 in the radial direction, and are formed to protrude from the flat portion 13a along the axis X. As shown in FIGS. 1 and 2, the annular portion 13 is provided with a plurality of protrusions 13b arranged at intervals in the circumferential direction CD, with their tips along the axis X protruding in a direction away from the blade 20 beyond a predetermined position spaced apart from the other end 11d of the outer wall portion 11 in the axis X direction by H1.

[0018] The position restricting portions 14 are members formed to protrude from each of a plurality of regions of the flat surface portion 13a that are arranged between the plurality of protruding portions 13b in the circumferential direction CD. The position restricting portions 14 are arranged more inward in the radial direction RAD than the outer wall portion 11, and restrict the radial position of the outer wall portions 11 of other stacked propeller fans 100. The position restricting portions 14 are formed to protrude along the axis X from each of a plurality of regions of the flat surface portion 13a that are arranged between the plurality of protruding portions 13b in the circumferential direction CD.

[0019] As shown in FIG. 4, the boss 15 is disposed on the inner side of the inner wall portion 12 in the radial direction RAD, and a rotary shaft 210 of a fan motor 200 that rotates around an axis X is attached to the boss 15.

[0020] As shown in FIG. 3, the connecting rib 16 is formed to extend along a radial direction perpendicular to the axis X, and is a member that connects the outer wall portion 11 and the inner wall portion 12 together.

[0021] The blades 20 are attached to the outer peripheral surface of the outer wall portion 11 of the hub 10 at three locations spaced apart in the circumferential direction CD about the axis X. Each blade 20 has a leading edge 20a located downstream in the rotation direction ROD and a trailing edge 20b located upstream in the rotation direction ROD. As shown in Fig. 2, the trailing edge 20b of each blade 20 is positioned so as to extend outward in the radial direction RAD from the radial outer edge of the protrusion 13b.

[0022] 5 and 6, a structure in which position restriction portion 14 restricts the radial position of outer wall portion 11 of other propeller fans 100 to be stacked will be described. Fig. 5 is a front view showing a state in which a plurality of propeller fans 100 are stacked. Fig. 6 is a cross-sectional view of propeller fan 100 shown in Fig. 5, taken along arrow BB.

[0023] 5, when one propeller fan 100 is stacked above another propeller fan 100, one end 11c on the upper side of outer wall portion 11 of the lower propeller fan 100 comes into contact with the other end 11d on the lower side of outer wall portion 11 of the upper propeller fan 100. Position restriction portion 14 protruding upward from flat portion 13a of lower propeller fan 100 is positioned radially inward of the other end 11d on the lower side of outer wall portion 11 of upper propeller fan 100.

[0024] As shown in Fig. 6, position restriction portions 14 of a lower propeller fan 100 are arranged radially inward at a small interval from the inner circumferential surfaces of outer wall portions 11 of other propeller fans 100 stacked above. Position restriction portions 14 are arranged at multiple locations spaced apart along the circumferential direction CD (three locations at 120-degree intervals in Fig. 6). Therefore, even if an operator accidentally applies a radial force to an upper propeller fan 100 stacked on a lower propeller fan 100, position restriction portions 14 prevent the upper propeller fan 100 from becoming misaligned.

[0025] Fig. 7 is a development view of the propeller fan shown in Fig. 2 developed in the circumferential direction. As shown in Fig. 7, recesses 11e having shapes corresponding to protrusions 13b are formed in the other end 11d of outer wall portion 11 at a plurality of positions in the circumferential direction CD corresponding to protrusions 13b. Therefore, when multiple propeller fans 100 are stacked, the multiple protrusions 13b of a lower propeller fan 100 are accommodated in the multiple recesses 11e of an upper propeller fan 100, and the overall height when multiple propeller fans 100 are stacked can be reduced.

[0026] The propeller fan 100 of the present embodiment described above provides the following functions and effects.

[0027] Propeller fan 100 of the present embodiment includes annular portion 13 formed in a ring shape along circumferential direction CD in a region sandwiched between outer wall portion 11 and inner wall portion 12 in a radial direction perpendicular to axis X. Annular portion 13 has a plurality of protruding portions 13b arranged at intervals in circumferential direction CD, and therefore can suppress damage to hub 10 due to a load applied from blades 20 to hub 10 in a direction pulling radially outward, compared to a case where annular portion 13 does not have protruding portions 13b.

[0028] Furthermore, according to propeller fan 100 of the present embodiment, a plurality of position restricting portions 14 are formed to protrude from each of a plurality of regions of annular portion 13 that are arranged between a plurality of protruding portions 13b in circumferential direction CD. Position restricting portions 14 are arranged radially inward of outer wall portion 11, and restrict the radial position of outer wall portion 11 of other stacked propeller fans 100. Therefore, it is possible to provide propeller fans 100 that will not become misaligned even if an operator accidentally applies a radial force to propeller fans 100 when stacking a plurality of propeller fans 100.

[0029] According to propeller fan 100 of the present embodiment, one end 11c of outer wall portion 11 and one end 12a of inner wall portion 12 are connected by flat portion 13a that is disposed on a plane perpendicular to axis X, and position restricting portions 14 protrude from each of multiple regions of flat portion 13a that are disposed between multiple protruding portions 13b. An operator stacking multiple propeller fans 100 can easily adjust the position of outer wall portion 11 of propeller fan 100 that is disposed above while visually checking position restricting portion 14 formed on flat portion 13a of propeller fan 100 that is disposed below, and stack the propeller fans 100 so that position restricting portion 14 is disposed radially inward of outer wall portion 11.

[0030] According to the propeller fan 100 of this embodiment, the trailing edge 20b of the blade 20 is positioned so as to extend radially outward from the radial outer edge of the protrusion 13b, thereby increasing the mounting angle of the blade 20 relative to the hub 10 and achieving low noise levels.

[0031] According to the propeller fan 100 of this embodiment, when multiple propeller fans 100 are stacked, the protrusion 13b of the propeller fan 100 arranged below can be stored in the recess 11e of the propeller fan 100 arranged above, thereby reducing the height of the stacked multiple propeller fans 100 and improving loading capacity.

[0032] [First Modified Example] Although annular portion 13 of propeller fan 100 described above has flat portions 13a and protruding portions 13b arranged alternately along circumferential direction CD, other configurations are also possible. For example, annular portion 13A of a first modified example shown in Fig. 8 may be used. Fig. 8 is a development view of annular portion 13A of the first modified example developed along the circumferential direction.

[0033] 8, the annular portion 13A of the first modified example has a plurality of protrusions 13b and a plurality of grooves 13c. The protrusions 13b and the grooves 13c are alternately arranged along the circumferential direction CD. The protrusions 13b are arranged at a plurality of locations spaced apart in the circumferential direction CD in a region sandwiched between the outer wall portion 11 and the inner wall portion 12 in the radial direction.

[0034] The grooves 13c are arranged at a plurality of locations between the pair of protruding portions 13b in the circumferential direction CD, and have a shape in which their tips along the axis X are recessed in a direction closer to the leading edge 20a of the blade 20 than a predetermined position spaced apart from the lower end by a distance H2 in the axis X direction. The position restriction portions 14 are formed to protrude from each of the grooves 13c.

[0035] According to the propeller fan 100 of the first modified example, an operator stacking multiple propeller fans 100 can adjust the position of the outer wall portion 11 of the propeller fan 100 placed above while visually checking the position regulating portion 14 formed in the groove portion 13c of the propeller fan 100 placed below, and can easily perform the stacking work so that the position regulating portion 14 is positioned radially inward of the outer wall portion 11.

[0036] [Second Modification] Although annular portion 13 of propeller fan 100 described above has flat portions 13a and protruding portions 13b arranged alternately along circumferential direction CD, other configurations are also possible. For example, annular portion 13B of a second modified example shown in Fig. 9 may be used. Fig. 9 is a development view of annular portion 13B of the second modified example developed along the circumferential direction.

[0037] 9, the annular portion 13B of the second modified example has a plurality of protrusions 13b and a plurality of grooves 13c. The protrusions 13b and the grooves 13c are alternately arranged along the circumferential direction CD. The protrusions 13b are arranged at a plurality of locations spaced apart in the circumferential direction CD in a region sandwiched between the outer wall portion 11 and the inner wall portion 12 in the radial direction.

[0038] The grooves 13c are arranged at a plurality of locations between the pair of protruding portions 13b in the circumferential direction CD, and have tips along the axis X that are recessed in a direction closer to the leading edge 20a of the blade 20 than a predetermined position spaced apart from the lower end by a distance H3 in the direction of the axis X. The position restriction portions 14 are formed to protrude from each of the protruding portions 13b.

[0039] According to the second modified example of the propeller fan 100, an operator stacking multiple propeller fans 100 can easily adjust the position of the outer wall portion 11 of the propeller fan 100 placed above while visually checking the position regulating portion 14 formed on the protrusion 13b of the propeller fan 100 placed below, and stack the propeller fans 100 so that the position regulating portion 14 is positioned radially inward of the outer wall portion 11.

[0040] The propeller fan (100) according to each of the above-described embodiments can be understood, for example, as follows.

[0041] A propeller fan according to a first aspect of the present disclosure includes a hub (10) that rotates about an axis (X), and a plurality of blades (20) attached to an outer peripheral surface of the hub at intervals in a circumferential direction about the axis, the hub including an outer wall portion (11) that is cylindrically formed to surround the axis, an inner wall portion (12) that is cylindrically formed to surround the axis and that is disposed inside the outer wall portion in a radial direction perpendicular to the axis, a boss (15) that is disposed inside the inner wall portion in the radial direction and to which a rotating shaft (210) that rotates about the axis is attached, and a boss (15) that is disposed on the inner side in the radial direction and to which a rotating shaft (210) that rotates about the axis is attached. The propeller fan is provided with: an annular portion (13) formed in a ring shape along the circumferential direction in a region sandwiched between the outer wall portion and the inner wall portion, and having a plurality of protrusions (13b) arranged at intervals in the circumferential direction, with their tips along the axis protruding in a direction away from the blades beyond a predetermined position; and a plurality of position control portions (14) formed to protrude from each of a plurality of regions of the annular portion arranged between the plurality of protrusions in the circumferential direction, arranged radially inward of the outer wall portion, and which control the radial position of the outer wall portion of other propeller fans that are stacked.

[0042] A propeller fan according to a first aspect of the present disclosure includes an annular portion formed in a circumferential direction in a region sandwiched between an outer wall portion and an inner wall portion in a radial direction perpendicular to the axis. The annular portion has a plurality of protrusions arranged at intervals in the circumferential direction, and therefore can suppress damage to the hub due to a load applied from the blades to the hub in a radially outward pulling direction, compared to a case where the annular portion does not have protrusions.

[0043] Furthermore, according to the propeller fan according to the first aspect of the present disclosure, a plurality of position restriction portions are formed to protrude from each of a plurality of regions of the annular portion that are disposed between the plurality of protrusions in the circumferential direction. The position restriction portions are disposed radially inward of the outer wall portion and restrict the radial position of the outer wall portions of other stacked propeller fans. This makes it possible to provide propeller fans that will not become misaligned even if an operator accidentally applies a radial force to a propeller fan when stacking multiple propeller fans.

[0044] A propeller fan according to a second aspect of the present disclosure is the first aspect, further comprising the following configuration: The annular portion has a flat portion (13a) that is arranged on a plane perpendicular to the axis and that is formed into an annular shape by connecting one end (11c) of the outer wall portion that is aligned with the axis and one end (12a) of the inner wall portion that is aligned with the axis, and a plurality of protruding portions (13b) that are arranged at a plurality of locations spaced apart in the circumferential direction in an area sandwiched between the outer wall portion and the inner wall portion in the radial direction and that protrude from the flat portion along the axis, and the position restricting portion is formed to protrude along the axis from each of a plurality of areas of the flat portion that are arranged between the plurality of protruding portions in the circumferential direction.

[0045] In the propeller fan according to the second aspect of the present disclosure, one end of the outer wall portion and one end of the inner wall portion are connected by a flat portion that is disposed on a plane perpendicular to the axis, and a position restricting portion protrudes from each of multiple regions of the flat portion that are disposed between the multiple protruding portions. An operator stacking multiple propeller fans can easily adjust the position of the outer wall portion of the propeller fan that is disposed above while visually checking the position restricting portion formed on the flat portion of the propeller fan that is disposed below, and stack the propeller fans so that the position restricting portion is disposed radially inward of the outer wall portion.

[0046] A propeller fan according to a third aspect of the present disclosure is the first aspect, further comprising the following configuration: The annular portion has a plurality of protrusions (13 a) arranged at a plurality of positions spaced apart in the circumferential direction in an area sandwiched between the outer wall portion and the inner wall portion in the radial direction, and a plurality of grooves (13 c) arranged at a plurality of positions sandwiched between a pair of the protrusions in the circumferential direction, and whose tips along the axis are recessed in a direction closer to the blades than the predetermined positions.

[0047] According to the propeller fan according to the third aspect of the present disclosure, a position restricting portion protrudes from each of a plurality of grooves disposed between a plurality of protrusions. An operator stacking a plurality of propeller fans can easily adjust the position of the outer wall portion of the propeller fan disposed above while visually checking the position restricting portion formed in the groove of the propeller fan disposed below, and stack the propeller fans so that the position restricting portion is disposed radially inward of the outer wall portion.

[0048] A propeller fan according to a fourth aspect of the present disclosure is the third aspect, further comprising the following configuration: the position restriction portion is formed so as to protrude from each of the plurality of groove portions in the circumferential direction.

[0049] According to the propeller fan according to the fourth aspect of the present disclosure, the position restriction portion formed in the groove restricts the radial position of the outer wall portion of other stacked propeller fans. Therefore, it is possible to provide propeller fans that will not become misaligned even if an operator accidentally applies a radial force to a propeller fan when stacking multiple propeller fans.

[0050] A propeller fan according to a fifth aspect of the present disclosure is the third aspect, further comprising the following configuration: the position restriction portion is formed so as to protrude from each of the plurality of protrusions in the circumferential direction.

[0051] According to the propeller fan according to the fifth aspect of the present disclosure, the position restricting portion formed on the protruding portion restricts the radial position of the outer wall portion of other stacked propeller fans. Therefore, it is possible to provide propeller fans that will not become misaligned even if an operator accidentally applies a radial force to a propeller fan when stacking multiple propeller fans.

[0052] A propeller fan according to a sixth aspect of the present disclosure is the propeller fan of any of the first to fifth aspects, further including the following configuration: Namely, the trailing edges (20b) of the blades are arranged to extend radially outward from the radially outer edges of the protruding portions.

[0053] According to the propeller fan of the sixth aspect of the present disclosure, the trailing edge of the blade is positioned to extend radially outward from the radial outer edge of the protrusion, thereby increasing the mounting angle of the blade relative to the hub and achieving low noise levels.

[0054] A propeller fan according to a seventh aspect of the present disclosure is any of the first to fifth aspects, further including the following configuration: Recesses (11e) having shapes corresponding to the protrusions are formed at the other end (11d) of the outer wall along the axis, at a plurality of positions in the circumferential direction corresponding to the protrusions.

[0055] According to the propeller fan of the seventh aspect of the present disclosure, when multiple propeller fans are stacked, the protruding portion of the lower propeller fan can be stored in the recessed portion of the upper propeller fan, thereby reducing the height of the stacked multiple propeller fans and improving loading capacity. [Explanation of symbols]

[0056] 10. Hub 11 Exterior wall 11a Outer surface 11b Inner surface 11c One end 11d Other end 11e Recess 12 Inner wall 12a One end 13, 13A, 13B Annular section 13a Flat part 13b Projection 13c Groove 14 Position regulation part 15. Boss 16 Connecting rib 20 wings 20a leading edge 20b Trailing edge 100 Propeller Fan 200 Fan motor 210 Rotational Axis CD circumferential direction RAD Radial direction Rod rotation direction X axis

Claims

1. A propeller fan, a hub that rotates about an axis; a plurality of blades attached to the outer peripheral surface of the hub at intervals in the circumferential direction around the axis, The hub includes: an outer wall portion formed in a cylindrical shape so as to surround the axis; an inner wall portion formed in a cylindrical shape so as to surround the axis and disposed radially inward relative to the outer wall portion in a direction perpendicular to the axis; a boss disposed radially inward relative to the inner wall portion, the boss having a rotary shaft attached thereto, the rotary shaft rotating about the axis; an annular portion formed in an area sandwiched between the outer wall portion and the inner wall portion in the radial direction and having a plurality of protruding portions arranged at intervals in the circumferential direction, the protruding portions having tips along the axis protruding in a direction away from the blade beyond a predetermined position; a plurality of position regulating portions that are formed to protrude from each of a plurality of regions of the annular portion that are arranged between a plurality of the protruding portions in the circumferential direction, that are arranged radially inward of the outer wall portion, and that regulate the radial position of the outer wall portion of other stacked propeller fans.

2. The annular portion is a flat portion that is disposed on a plane perpendicular to the axis and that is formed into an annular shape by connecting one end of the outer wall portion along the axis and one end of the inner wall portion along the axis; a plurality of protruding portions that are arranged at a plurality of locations spaced apart in the circumferential direction in a region sandwiched between the outer wall portion and the inner wall portion in the radial direction and that are formed to protrude from the flat portion along the axis, The position restriction portion is The propeller fan according to claim 1 , wherein the protrusions are formed so as to protrude along the axis from each of a plurality of regions of the flat surface that are arranged between the plurality of protrusions in the circumferential direction.

3. The annular portion is a plurality of the protrusions arranged at a plurality of locations spaced apart in the circumferential direction in a region sandwiched between the outer wall portion and the inner wall portion in the radial direction; 2. The propeller fan according to claim 1, further comprising: a plurality of grooves arranged at a plurality of locations in the circumferential direction between a pair of the protrusions, the grooves having tips along the axis that are recessed in a direction closer to the blade than the predetermined position.

4. The propeller fan according to claim 3 , wherein the position restriction portion is formed so as to protrude from each of the plurality of groove portions in the circumferential direction.

5. The propeller fan according to claim 3 , wherein the position restriction portion is formed so as to protrude from each of the plurality of protrusions in the circumferential direction.

6. The propeller fan according to claim 1 , wherein the trailing edges of the blades are arranged to extend radially outward from the radially outer edges of the protrusions.

7. 6. A propeller fan according to claim 1, wherein the other end of the outer wall portion along the axis has recesses having shapes corresponding to the protrusions formed at a plurality of positions in the circumferential direction corresponding to the protrusions.

Images