Propeller fan and air blower

Abstract

To provide a propeller fan capable of reducing noise more securely, and an air blower.SOLUTION: A propeller fan 5 is characterized in that each blade 7 has a blade pressure surface 8 facing a pressure side and a blade negative pressure surface 9 facing a negative pressure side formed therein. The blade negative pressure surface 9 has: a negative pressure body surface 91 formed at a blade body part 71 of the blade 7; and a negative pressure projection surface 92 formed at a blade projection part 72 of the blade 7 and protruding to a negative pressure side relative to the negative pressure body surface 91. The blade pressure surface 8 has: a pressure body surface 81 formed at the blade body part 71; and a pressure hollow surface 82 formed at the blade projection part 72 and hollowed to the pressure body surface 81. A rear edge 72b of the blade projection part 72 out of a front edge 72a and the rear edge 72b of the blade projection part 72 in a rotating direction of a boss 6 is located at a position distant from a rear edge 7b of the blade 7 to a side close to a front edge 7a of the blade 7.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a propeller fan in which each blade is curved toward the upstream side of the airflow as it moves radially away from the boss in order to suppress noise generated when multiple blades rotate around a rotation axis. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6837611 Summary of the Invention [Problem to be solved by the invention]

[0004] The conventional propeller fan disclosed in Patent Document 1 suppresses noise caused by tip vortices that occur around the outer periphery of each blade. However, with conventional propeller fans, separation vortices that occur around the leading edge of each blade in the direction of rotation of the blade tend to expand. Therefore, with conventional propeller fans, it is difficult to reduce noise.

[0005] The present disclosure is devised to solve the above-described problems, and has an object to provide a propeller fan and a blower that can more reliably reduce noise. [Means for solving the problem]

[0006] A propeller fan according to the present disclosure includes a boss that is rotatable around an axis, and a plurality of blades that are fixed to the outer periphery of the boss and are rotatable integrally with the boss around the axis, and each blade is formed with a blade pressure surface facing the pressure side, which is the front side of the blade in the rotation direction of the boss, and a blade suction surface facing the suction side, which is the rear side of the blade in the rotation direction of the boss, and each blade has a blade main body portion fixed to the boss and a blade protrusion portion connected to the blade main body portion, and the blade suction surface is formed by a negative pressure main body surface formed on the blade main body portion and a blade protrusion portion connected to the blade main body portion. The blade pressure surface has a pressure main body surface formed on the blade main body portion and a pressure recess surface formed on the blade protrusion portion and recessed relative to the pressure main body surface, and of the leading and trailing edges of the blade in the rotation direction of the boss, the trailing edge of the blade is the trailing edge of the blade main body portion in the rotation direction of the boss, and of the leading and trailing edges of the blade protrusion portion in the rotation direction of the boss, the trailing edge of the blade protrusion portion is located at a position away from the trailing edge of the blade toward the leading edge of the blade. [Effects of the Invention]

[0007] According to the present disclosure, noise can be reduced more reliably. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view showing a blower according to a first embodiment. [Figure 2] FIG. 2 is a perspective view showing the propeller fan of FIG. 1. [Figure 3] 2 is a cross-sectional view schematically showing a main part of the blower when cut along a plane passing through the axis Z in FIG. 1. [Figure 4] 3 is a plan view showing a main part of the propeller fan as viewed along the axis Z in FIG. 2. [Figure 5] FIG. 5 is a cross-sectional view taken along line VV in FIG. [Figure 6] FIG. 10 is a plan view showing a main part of a propeller fan in a blower of a comparative example when viewed along the axis of the propeller fan. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. [Figure 8] FIG. 7 is a perspective view schematically showing airflows generated around blades by rotation of the propeller fan of FIG. 6. [Figure 9] 8 is a cross-sectional view schematically showing the flow of air currents generated around the blade when the blade of FIG. 7 rotates in the rotation direction W of the boss. FIG. [Figure 10] 6 is a cross-sectional view schematically showing the flow of air currents generated around the blade when the blade of FIG. 5 rotates in the rotation direction W of the boss. FIG. [Figure 11] 6 is a graph showing the relationship between the projection thickness ratio tt / t in FIG. 5 and the noise reduction value. [Figure 12] 5 is a graph showing the relationship between the leading edge length ratio Lt1 / LZ of FIG. 4 and the noise reduction value. [Figure 13] FIG. 10 is a plan view showing a main part of a propeller fan in a blower according to a second embodiment. [Figure 14] FIG. 14 is a cross-sectional view taken along line XIV-XIV in FIG. [Figure 15] 10 is a graph showing the relationship between the outer peripheral edge position protrusion ratio LT / LC and the noise reduction value. [Figure 16] FIG. 11 is a plan view showing a main part of a propeller fan in a blower according to a third embodiment. [Figure 17] FIG. 10 is a plan view showing a main part of a propeller fan in a blower according to a fourth embodiment. [Figure 18] 10 is a graph showing noise reduction values ​​for fans according to each of the first, third, and fourth embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0009] The following describes embodiments of the subject matter of the present disclosure with reference to the accompanying drawings. In each drawing, identical or corresponding parts are designated by the same reference numerals, and redundant explanations are appropriately simplified or omitted. Note that the subject matter of the present disclosure is not limited to the following embodiments, and any component of the embodiments may be modified or omitted within the scope of the gist of the present disclosure.

[0010] Embodiment 1 1 is a perspective view showing a blower according to Embodiment 1. Blower 1, which is an axial flow blower, has an attachment base 2, a bell mouth 3, a main shaft 4, a motor (not shown), and a propeller fan 5.

[0011] The mounting base 2 is attached, for example, indoors. The mounting base 2 has a circular opening 21 formed therein.

[0012] The spindle 4 and the motor are supported by the mounting base 2 via fixing members (not shown). The spindle 4 and the motor are disposed at the center of the opening 21. The axis Z of the spindle 4 coincides with the center line of the opening 21.

[0013] The bell mouth 3 is fixed to the mounting base 2. The bell mouth 3 is a cylindrical member that fits along the inner circumferential surface of the opening 21. The axis of the bell mouth 3 coincides with the center line of the opening 21.

[0014] The propeller fan 5 is disposed inside the bell mouth 3. The propeller fan 5 is attached to the main shaft 4. The axis of the propeller fan 5 coincides with the axis Z of the main shaft 4. The propeller fan 5 rotates relative to the mounting base 2 and the bell mouth 3 around the axis Z of the main shaft 4 by the driving force of the motor.

[0015] Fig. 2 is a perspective view showing the propeller fan 5 of Fig. 1. The propeller fan 5 has a boss 6 and a plurality of blades 7.

[0016] The boss 6 has a boss main body 61 and multiple spider portions 62. The boss main body 61 is attached to the main shaft 4. The multiple spider portions 62 protrude from the outer periphery of the boss main body 61 radially outward of the boss 6 as blade fixing portions. The multiple spider portions 62 are arranged at intervals from one another in the circumferential direction of the boss 6. The boss 6 is formed by bending a single plate with a constant thickness. The boss 6 is rotatable around the axis Z of the main shaft 4.

[0017] The multiple blades 7 are individually fixed to the multiple spider portions 62 by welding or rivets. In this way, the multiple blades 7 are fixed to the outer periphery of the boss 6. The multiple blades 7 are arranged at intervals from one another in the circumferential direction of the boss 6. Each blade 7 extends radially outward from the boss 6 beyond the spider portions 62.

[0018] The multiple blades 7 are rotatable integrally with the boss 6 around the axis Z of the main shaft 4. In the blower 1, the multiple blades 7 rotate integrally with the boss 6 around the axis Z, generating an airflow that flows in a direction along the axis Z of the main shaft 4 as a fan airflow. In this embodiment, the multiple blades 7 rotate integrally with the boss 6 in the rotation direction W in FIG. 2, generating a fan airflow. The flow direction A of the fan airflow is along the axis Z.

[0019] Fig. 3 is a cross-sectional view schematically showing the main parts of blower 1 when cut along a plane passing through axis Z in Fig. 1. Bellmouth 3 has a reduced diameter section 31, an intermediate section 32, and an expanded diameter section 33. Reduced diameter section 31 is located upstream of intermediate section 32 in flow direction A of the fan airflow. Intermediate section 32 is located upstream of expanded diameter section 33 in flow direction A of the fan airflow.

[0020] The inner diameter of the reduced diameter section 31 continuously decreases toward the intermediate section 32. The inner diameter of the intermediate section 32 is constant at any position in the flow direction A of the fan airflow. The inner diameter of the expanded diameter section 33 continuously increases with increasing distance from the intermediate section 32. In this embodiment, in a cross section of the bell mouth 3 taken on a plane passing through the axis Z, the radius of curvature Rin of the inner surface of the reduced diameter section 31 is larger than the radius of curvature Rout of the inner surface of the expanded diameter section 33. Also, in this embodiment, in at least a part of the range of the length ST of the intermediate section 32 in the direction along the axis Z, the outer periphery of the propeller fan 5 faces the inner periphery of the bell mouth 3 via a gap. The fan airflow sucked into the bell mouth 3 flows inside the bell mouth 3, passing through the reduced diameter section 31, the intermediate section 32, and the expanded diameter section 33 in that order, and is thereby straightened before being discharged from the bell mouth 3.

[0021] Fig. 4 is a plan view showing a main part of the propeller fan 5 as viewed along the axis Z in Fig. 2. In the propeller fan 5, all of the spider portions 62 have the same configuration, and all of the blades 7 have the same configuration, so Fig. 4 shows one spider portion 62 and one blade 7.

[0022] Figure 5 is a cross-sectional view taken along line VV in Figure 4. In Figure 4, the portion of an imaginary cylindrical surface centered on axis Z that crosses the blade 7 is shown as line VV. Therefore, Figure 5 shows a cross section of the blade 7 when cut by an imaginary cylindrical surface centered on axis Z.

[0023] 5, each blade 7 is formed with a blade pressure surface 8 and a blade suction surface 9. The blade pressure surface 8 and the blade suction surface 9 face opposite sides to each other in the thickness direction of the blade 7.

[0024] Each blade 7 is arranged with its blade pressure surface 8 and blade suction surface 9 inclined with respect to the rotation direction W of the boss 6. In each blade 7, the blade pressure surface 8 faces the pressure side, which is the front side of the blade 7 in the rotation direction W of the boss 6, and the blade suction surface 9 faces the suction side, which is the rear side of the blade 7 in the rotation direction W of the boss 6.

[0025] When each blade 7 rotates integrally with the boss 6 about the axis Z, the blade pressure surface 8 receives air present on the pressure side of the blade 7, and the pressure on the blade pressure surface 8 increases. On the other hand, when each blade 7 rotates integrally with the boss 6 about the axis Z, the pressure on the blade suction surface 9 decreases. When each blade 7 rotates about the axis Z, the blade pressure surface 8 pushes out the air present on the pressure side of the blade 7, generating a fan airflow.

[0026] As shown in Figure 4, the edge of each blade 7 located on the front side in the rotation direction W of the boss 6 is the leading edge 7a of the blade 7, and the edge located on the rear side in the rotation direction W of the boss 6 is the trailing edge 7b of the blade 7. The leading edge 7a of the blade 7 extends and curves forward in the rotation direction W of the boss 6 as it moves radially outward of the boss 6. The trailing edge 7b of the blade 7 extends and curves forward in the rotation direction W of the boss 6 as it moves radially outward of the boss 6.

[0027] Of both ends of the leading edge 7a of the blade 7, the end located radially outward from the boss 6 is the leading-edge outer end 7d, and the end located radially inward from the boss 6 is the leading-edge inner end 7e. Of both ends of the trailing edge 7b of the blade 7, the end located radially outward from the boss 6 is the trailing-edge outer end 7f, and the end located radially inward from the boss 6 is the trailing-edge inner end 7g.

[0028] Furthermore, the edge of each blade 7 positioned radially outward from the boss 6 is the outer peripheral edge 7c of the blade 7. When the blade 7 is viewed along the axis Z, the outer peripheral edge 7c of the blade 7 extends along a circle centered on the axis Z. The outer peripheral edge 7c of the blade 7 extends from the outer leading edge end 7d to the outer trailing edge end 7f. In this embodiment, the outer periphery of the blade 7, including the outer peripheral edge 7c, is bent upstream in the flow direction A of the fan airflow.

[0029] Each blade 7 has a blade main body 71 and a blade protrusion 72. The blade main body 71 is fixed to the spider portion 62 of the boss 6. In this embodiment, the spider portion 62 overlaps the blade suction surface 9. The blade protrusion 72 is connected to the blade main body 71. Each blade 7 is made of a plate with a constant thickness. Therefore, the thickness of each blade 7 is constant. The thickness of each spider portion 62 is thicker than the thickness of the blade main body 71. Note that the blade protrusion 72 of each blade 7 is not shown in Figure 3.

[0030] The edge of the blade main body 71 located on the front side in the rotation direction W of the boss 6 is the leading edge 71a of the blade main body 71, and the edge located on the rear side in the rotation direction W of the boss 6 is the trailing edge 71b of the blade main body 71. The leading edge 71a of the blade main body 71 is formed as part of the leading edge 7a of the blade 7. The trailing edge 71b of the blade main body 71 is formed as the trailing edge 7b of the blade 7. In other words, the entire trailing edge 7b of the blade 7 is the trailing edge 71b of the blade main body 71.

[0031] Furthermore, the edge of the blade main body 71 located radially outward of the boss 6 constitutes the outer peripheral edge 71c of the blade main body 71. The outer peripheral edge 71c of the blade main body 71 is formed as the outer peripheral edge 7c of the blade 7. In other words, the entire outer peripheral edge 7c of the blade 7 constitutes the outer peripheral edge 71c of the blade main body 71.

[0032] In the wing protrusion portion 72, the edge located on the front side in the rotation direction W of the boss 6 is the leading edge 72a of the wing protrusion portion 72, and the edge located on the rear side in the rotation direction W of the boss 6 is the trailing edge 72b of the wing protrusion portion 72.

[0033] The leading edge 72a of the wing protrusion 72 is formed as part of the leading edge 7a of the wing 7. The leading edge 71a of the wing main body 71 and the leading edge 72a of the wing protrusion 72 are formed continuously as the leading edge 7a of the wing 7.

[0034] The leading edge 72a of the wing protrusion 72 is located at the middle of the leading edge 7a of the blade 7. Of both ends of the leading edge 72a of the wing protrusion 72, the end located radially outward from the boss 6 is the protrusion leading edge outer end 72c, and the end located radially inward from the boss 6 is the protrusion leading edge inner end 72d. The leading edge 72a of the wing protrusion 72 is connected to the leading edge 71a of the blade main body 71 at both the protrusion leading edge outer end 72c and the protrusion leading edge inner end 72d.

[0035] The trailing edge 72b of the wing protrusion 72 is located at a position away from the trailing edge 7b of the wing 7 toward the leading edge 7a of the wing 7. In this embodiment, the trailing edge 72b of the wing protrusion 72 is located at a position closer to the leading edge 7a of the wing 7 than the trailing edge 7b of the wing 7.

[0036] Of the two ends of the trailing edge 72b of the wing protrusion 72, the end located radially outward from the boss 6 is the protrusion trailing edge outer end 72e, and the end located radially inward from the boss 6 is the protrusion trailing edge inner end 72f.

[0037] Furthermore, the edge of the wing protrusion portion 72 that is located on the outer side in the radial direction of the boss 6 is the outer peripheral edge 72g of the wing protrusion portion 72, and the edge that is located on the inner side in the radial direction of the boss 6 is the inner peripheral edge 72h of the wing protrusion portion 72.

[0038] An outer peripheral edge 72g of the wing protrusion 72 is connected to each of the protrusion leading edge outer end 72c and the protrusion trailing edge outer end 72e. An inner peripheral edge 72h of the wing protrusion 72 is connected to each of the protrusion leading edge inner end 72d and the protrusion trailing edge inner end 72f.

[0039] The blade protrusion 72 is connected to the blade main body 71 over the entire area of ​​the trailing edge 72b, the outer peripheral edge 72g, and the inner peripheral edge 72h.

[0040] As shown in Fig. 5, the blade suction surface 9 is formed continuously with the blade main body 71 and the blade protrusion 72. As a result, the blade suction surface 9 has a negative pressure main body surface 91 formed on the blade main body 71 and a negative pressure protrusion surface 92 formed on the blade protrusion 72. The negative pressure protrusion surface 92 is continuous with the negative pressure main body surface 91, with the trailing edge 72b, the outer peripheral edge 72g, and the inner peripheral edge 72h as boundaries. The negative pressure protrusion surface 92 protrudes from the negative pressure main body surface 91 towards the negative pressure side of the blade 7.

[0041] The blade pressure surface 8 is formed continuously with the blade main body 71 and the blade protrusion 72. As a result, the blade pressure surface 8 has a pressure main body surface 81 formed on the blade main body 71 and a pressure recessed surface 82 formed on the blade protrusion 72. The pressure recessed surface 82 is continuous with the pressure main body surface 81, with the trailing edge 72b, the outer peripheral edge 72g, and the inner peripheral edge 72h as boundaries. The pressure recessed surface 82 is recessed with respect to the pressure main body surface 81.

[0042] The leading edge 7a of the blade 7 is shaped such that the leading edge 72a of the blade protrusion 72 protrudes toward the suction side of the blade 7 relative to the leading edge 71a of the blade main body 71, and is recessed toward the pressure side of the blade 7 relative to the leading edge 71a of the blade main body 71. The leading edges 71a of the blade main body 71 are located on both sides of the leading edge 72a of the blade protrusion 72 in the radial direction of the boss 6. As a result, the leading edge 7a of the blade 7 is shaped such that the middle portion of the leading edge 7a of the blade 7 protrudes toward the suction side of the blade 7, and is recessed toward the pressure side of the blade 7.

[0043] The blade main body 71 and the blade protrusion 72 are formed by plastically deforming a single raw material plate having a certain thickness by press working. In the press working of the raw material plate, a part of the raw material plate is made to protrude in the thickness direction of the raw material plate as the blade protrusion 72, and the part other than the blade protrusion 72 is formed as the blade main body 71, thereby forming the blade 7.

[0044] As shown in Fig. 5, the blade protrusion 72 has an offset portion 721 and a connecting portion 722. The offset portion 721 is disposed offset toward the negative pressure side of the blade 7 with respect to the blade main body 71. The connecting portion 722 connects the outer periphery of the offset portion 721 to the blade main body 71. The connecting portion 722 is disposed along the trailing edge 72b, outer periphery 72g, and inner periphery 72h of the blade protrusion 72. No connecting portion 722 is disposed at the leading edge 72a of the blade protrusion 72.

[0045] The negative pressure protrusion surface 92 is formed continuously with the offset portion 721 and the connecting portion 722. As a result, the negative pressure protrusion surface 92 has a negative pressure protrusion upper end surface 921 formed on the offset portion 721 and a negative pressure protrusion outer peripheral surface 922 formed on the connecting portion 722. The negative pressure protrusion outer peripheral surface 922 is formed along each of the trailing edge 72b, outer peripheral edge 72g, and inner peripheral edge 72h of the blade protrusion 72. As a result, a step is formed between the negative pressure protrusion upper end surface 921 and the negative pressure main surface 91 on the blade suction surface 9. In this embodiment, the negative pressure protrusion upper end surface 921 is a flat surface. Also, in this embodiment, the negative pressure protrusion outer peripheral surface 922 is a surface that is perpendicular to each of the negative pressure protrusion upper end surface 921 and the negative pressure main surface 91.

[0046] The pressure recess surface 82 is formed continuously with the offset portion 721 and the connecting portion 722. The pressure recess surface 82 is formed in the offset portion 721 and the connecting portion 722 following the shapes of the negative pressure projection upper end surface 921 and the negative pressure projection outer peripheral surface 922.

[0047] 4, the total length of the leading edge 7a of the blade 7 is defined as the blade leading edge length LZ. The length of the leading edge 72a of the blade protrusion 72 is defined as the protrusion leading edge length Lt1, and the length of the trailing edge 72b of the blade protrusion 72 is defined as the protrusion trailing edge length Lt2. The length of the outer peripheral edge 72g of the blade protrusion 72 is defined as the protrusion outer peripheral edge length Lt3, and the length of the inner peripheral edge 72h of the blade protrusion 72 is defined as the protrusion inner peripheral edge length Lt4.

[0048] In this embodiment, the protrusion leading edge length Lt1 and the protrusion trailing edge length Lt2 are longer than the protrusion outer peripheral edge length Lt3 and the protrusion inner peripheral edge length Lt4. Also, in this embodiment, the protrusion leading edge length Lt1 is longer than the protrusion trailing edge length Lt2, and the protrusion outer peripheral edge length Lt3 is longer than the protrusion inner peripheral edge length Lt4. Furthermore, in this embodiment, the blade leading edge length LZ is longer than the protrusion leading edge length Lt1.

[0049] Next, a comparative example of a blower for comparison with blower 1 according to the present embodiment will be described. Fig. 6 is a plan view showing a main part of a propeller fan in the comparative example of a blower as viewed along the axis of the propeller fan. Fig. 7 is a cross-sectional view taken along line VII-VII in Fig. 6. Fig. 6 is a view corresponding to Fig. 4 in the first embodiment, and Fig. 7 is a view corresponding to Fig. 5 in the first embodiment. Fig. 7 shows a cross section of a blade when the blade is cut by an imaginary cylindrical surface centered on the axis of the propeller fan.

[0050] In the comparative example, propeller fan 500 is rotatable about axis Z. In the comparative example, each blade 700 of propeller fan 500 is formed with a blade pressure surface 8 and a blade suction surface 9. In the comparative example, blade pressure surface 8 faces the pressure side of blade 700, and blade suction surface 9 faces the suction side of blade 700. In the comparative example, the entire blade pressure surface 8 is a smooth surface without protruding or recessed surfaces, and the entire blade suction surface 9 is a smooth surface without protruding or recessed surfaces. Other configurations of the blower of the comparative example are similar to those of blower 1 according to embodiment 1.

[0051] Next, we will explain the airflow generated around the blades 700 when the propeller fan 500 in the blower of the comparative example rotates about the axis Z. FIG. 8 is a perspective view that schematically shows the airflow generated around the blades 700 due to the rotation of the propeller fan 500 in FIG. 6. When each blade 700 rotates in the rotation direction W, a fan airflow is generated that flows in the flow direction A. At this time, a leading-edge separation vortex 10 is generated at the leading edge 7a of each blade 700, and a wake vortex 11 is generated at the trailing edge 7b of each blade 700. At this time, a blade tip vortex 12 is generated at the outer peripheral edge 7c of each blade 7. As a result, when each blade 700 rotates integrally with the boss 6, noise is generated due to the leading-edge separation vortex 10, the wake vortex 11, and the blade tip vortex 12.

[0052] 9 is a cross-sectional view schematically showing the flow of air currents generated around the blade 700 when the blade 700 in FIG. 7 rotates in the rotation direction W of the boss 6. In the blower of the comparative example, when the blade 700 rotates in the rotation direction W, a pressure-side air current 13 flows on the pressure side of the blade 700 from the leading edge 7a to the trailing edge 7b of the blade 700, and a suction-side air current 14 flows on the suction side of the blade 700 from the leading edge 7a to the trailing edge 7b of the blade 700.

[0053] At this time, at the leading edge 7a of the blade 700, the suction side airflow 14 separates from the blade 700, generating a leading-edge separation vortex 10. This causes turbulence in the suction side airflow 14 at the leading edge 7a of the blade 700. The suction side airflow 14, disturbed by the leading-edge separation vortex 10, then flows toward the trailing edge 7b of the blade 700. As a result, the turbulence of the suction side airflow 14 caused by the leading-edge separation vortex 10 affects the wake vortex 11 generated at the trailing edge 7b of the blade 700. Therefore, the larger the leading-edge separation vortex 10, the greater the turbulence of the wake vortex 11. As a result, when each blade 700 rotates integrally with the boss 6 in the rotation direction W, the larger the leading-edge separation vortex 10 becomes, the greater the noise caused by each of the leading-edge separation vortex 10 and the wake vortex 11 becomes.

[0054] Next, we will explain the airflow generated around the blades 7 when the propeller fan 5 in the blower 1 according to this embodiment rotates about the axis Z. In the blower 1 according to this embodiment, when each blade 7 rotates in the rotation direction W of the boss 6, a leading edge separation vortex 10 is generated at the leading edge 7a of each blade 7, and a wake vortex 11 is generated at the trailing edge 7b of each blade 7, just like in the comparative example. In addition, a blade tip vortex 12 is generated at the outer peripheral edge 7c of each blade 7.

[0055] FIG. 10 is a cross-sectional view schematically illustrating the airflow generated around the blade 7 when the blade 7 of FIG. 5 rotates in the rotation direction W of the boss 6. When the blade 7 rotates in the rotation direction W of the boss 6, as in the comparative example, the pressure-side airflow 13 flows from the leading edge 7a to the trailing edge 7b of the blade 7 along the pressure side of the blade 7, and the suction-side airflow 14 flows from the leading edge 7a to the trailing edge 7b of the blade 7 along the suction side of the blade 7. At this time, the suction-side airflow 14 temporarily separates at the leading edge 72a of the blade protrusion 72. However, turbulence occurs in part of the suction-side airflow 14 behind the trailing edge 72b of the blade protrusion 72 in the rotation direction W of the boss 6. As a result, the suction-side airflow 14, once separated at the leading edge 72a of the blade protrusion 72, is less likely to separate from the blade suction surface 9, and the magnitude of separation of the suction-side airflow 14 from the blade suction surface 9 is reduced compared to the comparative example. Therefore, the size of the leading-edge separation vortex 10 generated at the leading edge 7a of the blade 7 is smaller than in the comparative example, and the flow of the suction-side airflow 14 is stably controlled along the blade suction surface 9. As a result, the size of the trailing vortex 11 generated at the trailing edge 7b of the blade 7 is also smaller than in the comparative example. As a result, when each blade 7 rotates in the rotation direction W of the boss 6, the noise caused by the leading-edge separation vortex 10 and the trailing vortex 11 is reduced compared to the comparative example.

[0056] Furthermore, in blower 1 according to this embodiment, outer peripheral edge 7c of each blade 7 is bent upstream in fan airflow direction A. This prevents tip vortices 12 from expanding at outer peripheral edge 7c of each blade 7 when each blade 7 rotates in rotation direction W of boss 6. This also reduces noise caused by tip vortices 12.

[0057] 5, the thickness of the offset portion 721 is defined as the protrusion thickness t, and the distance by which the offset portion 721 is shifted toward the suction side relative to the blade main body 71 is defined as the protrusion height tt. The ratio of the protrusion height tt to the protrusion thickness t is defined as the protrusion thickness ratio tt / t.

[0058] Fig. 11 is a graph showing the relationship between the protrusion thickness ratio tt / t of Fig. 5 and the noise reduction value [dB]. The noise reduction value [dB] is the value of the volume reduced from the noise value generated by the fan of the comparative example. As shown in Fig. 11, when the protrusion thickness ratio tt / t is in the range greater than 0, the noise is reduced compared to the comparative example.

[0059] If the range of noise reduction values ​​at which the target noise reduction effect can be achieved is defined as -0.5 dB or greater, it can be seen from Fig. 11 that the target noise reduction effect can be achieved in the range of 0.42 ≦ protrusion thickness ratio tt / t ≦ 5.1. In other words, it can be seen that the target noise reduction effect can be achieved when the protrusion thickness ratio tt / t is in the range of 0.42 or greater and 5.1 or less. In this embodiment, the protrusion thickness ratio tt / t is set in the range of 0.42 or greater and 5.1 or less. Note that a range of -0.5 dB or greater means that the absolute value is 0.5 or greater.

[0060] Figure 12 is a graph showing the relationship between the ratio of the protrusion leading edge length Lt1 to the blade leading edge length LZ in Figure 4, i.e., the leading edge length ratio Lt1 / LZ, and the noise reduction value [dB]. In Figure 12, when the position of the blade leading edge inner end 7e is set to 0 and the position of the blade leading edge outer end 7d is set to 1, the position of the protrusion leading edge outer end 72c is set to a protrusion reference position where the ratio becomes 0.765 in the direction along the leading edge 7a of the blade 7. Figure 12 shows the relationship between the leading edge length ratio Lt1 / LZ and the noise reduction value [dB] when the position of the protrusion leading edge outer end 72c is set to the protrusion reference position.

[0061] In each blade 7, as the leading edge length ratio Lt1 / LZ decreases, the protrusion leading edge length Lt1 decreases, and the size of the blade protrusion 72 decreases. Therefore, as the leading edge length ratio Lt1 / LZ decreases, the noise reduction value [dB] decreases, and the noise reduction effect decreases, as shown in FIG. 12 . That is, as the leading edge length ratio Lt1 / LZ increases, the noise reduction value [dB] increases, and the noise reduction effect improves. If the range of noise reduction values ​​at which a target noise reduction effect can be achieved is defined as -0.5 [dB] or greater, as shown in FIG. 12 , it can be seen that the target noise reduction effect can be achieved when the leading edge length ratio Lt1 / LZ is 0.045 or greater, i.e., in the range of 0.045 or greater. In this embodiment, the leading edge length ratio Lt1 / LZ is set to a range of 0.045 or greater.

[0062] In such a propeller fan 5 and blower 1, each blade 7 is formed with a blade pressure surface 8 facing the pressure side of the blade 7 and a blade suction surface 9 facing the suction side of the blade 7. The blade pressure surface 8 has a pressure main surface 81 formed on the blade main body 71 of the blade 7 and a pressure recessed surface 82 formed on the blade protrusion 72 of the blade 7. The blade suction surface 9 has a negative pressure main surface 91 formed on the blade main body 71 of the blade 7 and a negative pressure protrusion surface 92 formed on the blade protrusion 72 of the blade 7. The negative pressure protrusion surface 92 protrudes toward the suction side of the blade 7 relative to the negative pressure main surface 91, and the pressure recessed surface 82 is recessed relative to the pressure main surface 81. The trailing edge 72b of the blade protrusion 72 is located away from the trailing edge 7b of the blade 7 toward the leading edge 7a of the blade 7.

[0063] Therefore, when each blade 7 rotates integrally with the boss 6, airflow turbulence can be generated behind the blade protrusion 72 in the rotation direction W of the boss 6, and the size of the airflow that separates from the blade 7 at the leading edge 72a of the blade protrusion 72 can be prevented from increasing. This allows the suction side airflow 14 that flows on the suction side of the blade 7 from the leading edge 7a to the trailing edge 7b of the blade 7 to be stably controlled along the blade suction surface 9, and the expansion of the leading-edge separation vortex 10 and the trailing vortex 11 can be prevented. Therefore, even if the flow rate of the fan airflow generated by the rotation of each blade 7 changes, for example, airflow turbulence can be generated behind the blade protrusion 72 in the rotation direction W of the boss 6, and the expansion of the leading-edge separation vortex 10 and the trailing vortex 11 can be prevented. This more reliably reduces noise caused by the leading-edge separation vortex 10 and the trailing vortex 11, and more reliably reduces noise when each blade 7 rotates integrally with the boss 6.

[0064] Furthermore, the shape of the blades 7 can be easily formed simply by protruding a portion of a raw material plate having a certain thickness in the thickness direction of the raw material plate. This makes it possible to easily form the shape of the blades 7 from the raw material plate, thereby reducing the effort required to manufacture the blades 7. Therefore, it is possible to more reliably reduce noise while suppressing an increase in the cost of the propeller fan 5.

[0065] Furthermore, the leading edge 72a of the blade protrusion 72 and the leading edge 71a of the blade main body 71 are continuously formed as the leading edge 7a of the blade 7. The leading edge 7a of the blade 7 is shaped so that the leading edge 72a of the blade protrusion 72 protrudes toward the suction side of the blade 7 relative to the leading edge 71a of the blade main body 71, and is recessed toward the pressure side of the blade 7 relative to the leading edge 71a of the blade main body 71. This effectively suppresses the magnitude of separation of the suction side airflow 14 at the leading edge 72a of the blade protrusion 72, among the leading edges 7a of the blade 7. This further ensures a reduction in noise caused by the leading edge separation vortex 10 and the wake vortex 11, and further ensures a reduction in noise when each blade 7 rotates integrally with the boss 6.

[0066] Furthermore, the protrusion leading edge length Lt1 is longer than the protrusion trailing edge length Lt2. This makes it possible to more stably control the suction side airflow 14 that flows on the suction side of the blade 7 from the leading edge 7a to the trailing edge 7b of the blade 7 along the blade suction surface 9. This makes it possible to more reliably reduce noise when each blade 7 rotates integrally with the boss 6.

[0067] The blades 7 have a uniform thickness. The ratio of the protrusion height tt to the protrusion thickness t, i.e., the protrusion thickness ratio tt / t, is set in the range of 0.42 to 5.1. This more reliably ensures a sufficient noise reduction value, further reducing noise when the blades 7 rotate integrally with the boss 6.

[0068] Furthermore, the thickness of each of the multiple spider portions 62 on the boss 6 is greater than the thickness of the blade main body portion 71. This increases the strength of the portion where the blade 7 is fixed to the boss 6. This more reliably suppresses deformation of the boss 6. This therefore stably reduces noise when each blade 7 rotates integrally with the boss 6.

[0069] Furthermore, the propeller fan 5 is disposed inside the bell mouth 3. Therefore, the fan airflow generated when the propeller fan 5 rotates can be rectified inside the bell mouth 3. This makes it possible to efficiently generate the fan airflow while reducing noise when the blades 7 rotate integrally with the boss 6.

[0070] Furthermore, the ratio of the projection leading edge length Lt1 to the blade leading edge length LZ, i.e., the leading edge length ratio Lt1 / LZ, is set to a range of 0.045 or greater, which further ensures a reduction in noise when each blade 7 rotates integrally with the boss 6.

[0071] In the first embodiment, the distance between the outer peripheral edge 7c of the blade 7 and the outer peripheral edge 72g of the blade protrusion 72 in the radial direction of the boss 6 may be set to be equal to or greater than the protrusion outer peripheral edge length Lt3. This prevents the outer peripheral edge 7c of the blade 7 from being deformed due to the plastic deformation of the raw material plate that accompanies the formation of the blade protrusion 72 when the raw material plate is pressed to form the blade protrusion 72. In this case, setting the distance between the outer peripheral edge 7c of the blade 7 and the outer peripheral edge 72g of the blade protrusion 72 to the same as the protrusion outer peripheral edge length Lt3 prevents the protrusion leading edge length Lt1 from being unnecessarily short. Therefore, by setting the distance between the outer peripheral edge 7c of the blade 7 and the outer peripheral edge 72g of the blade protrusion 72 to the same as the protrusion outer peripheral edge length Lt3, deformation of the outer peripheral edge 7c of the blade 7 is suppressed, while preventing the noise reduction effect of the blade protrusion 72 from being unnecessarily reduced.

[0072] Embodiment 2 Fig. 13 is a plan view showing a main part of a propeller fan in a blower according to embodiment 2. Fig. 14 is a cross-sectional view taken along line XIV-XIV in Fig. 13. Fig. 13 corresponds to Fig. 4 in embodiment 1, and Fig. 14 corresponds to Fig. 5 in embodiment 1. In Fig. 13, the portion of an imaginary cylindrical plane centered on axis Z that crosses blade protrusion 72 is shown as line XIV-XIV. Therefore, Fig. 14 shows a cross section of blade 7 when blade 7 is cut by an imaginary cylindrical plane centered on axis Z.

[0073] The leading edge 72a of the wing protrusion 72 is located away from the leading edge 7a of the wing 7 toward the trailing edge 7b of the wing 7. As a result, the entire leading edge 7a of the wing 7 becomes the leading edge 71a of the wing main body 71. Therefore, the shape of the leading edge 7a of the wing 7 is smooth and free of protrusions over the entire area. The leading edge 72a of the wing protrusion 72 is formed parallel to the leading edge 7a of the wing 7.

[0074] In the wing protrusion 72, a connecting portion 722 connects the offset portion 721 to the wing main body 71 over the entire outer periphery of the offset portion 721. Therefore, the connecting portion 722 is arranged along each of the leading edge 72a, the trailing edge 72b, the outer periphery 72g, and the inner periphery 72h of the wing protrusion 72.

[0075] The negative pressure protrusion surface 92 is formed continuously with the offset portion 721 and the connecting portion 722. Therefore, the negative pressure protrusion outer peripheral surface 922 formed on the connecting portion 722 is formed along each of the leading edge 72a, the trailing edge 72b, the outer peripheral edge 72g, and the inner peripheral edge 72h of the wing protrusion 72. In other words, the negative pressure protrusion outer peripheral surface 922 is formed around the entire periphery of the wing protrusion 72. In this embodiment, the negative pressure protrusion outer peripheral surface 922 is a surface that is perpendicular to each of the negative pressure protrusion upper end surface 921 and the negative pressure main body surface 91.

[0076] The pressure recess surface 82 is formed continuously with the offset portion 721 and the connecting portion 722. The pressure recess surface 82 is formed in the offset portion 721 and the connecting portion 722 following the shapes of the negative pressure projection upper end surface 921 and the negative pressure projection outer peripheral surface 922.

[0077] 13, in a cross section of the blade 7 taken along a reference imaginary cylindrical plane Q, which is an imaginary cylindrical plane that passes through the protrusion leading edge outer end 72c and is centered on the axis Z, the straight-line distance from the leading edge 7a of the blade 7 to the trailing edge 7b of the blade 7 is defined as the reference chord length LC. In addition, in a cross section of the blade 7 taken along the reference imaginary cylindrical plane Q, the straight-line distance from the leading edge 7a of the blade 7 to the protrusion leading edge outer end 72c is defined as the first protrusion distance LT.

[0078] Fig. 15 is a graph showing the relationship between the ratio of the first protrusion distance LT to the reference chord length LC, i.e., the outer peripheral position protrusion ratio LT / LC, and the noise reduction value [dB]. If the range of noise reduction values ​​in which the target noise reduction effect can be achieved is defined as a range of -0.5 [dB] or more, Fig. 15 shows that the target noise reduction effect can be achieved in the range of 0≦outer peripheral position protrusion ratio LT / LC≦0.65. In other words, it can be seen that the target noise reduction effect can be achieved when the outer peripheral position protrusion ratio LT / LC is a value in the range of 0 or more and 0.65 or less.

[0079] In this embodiment, the outer peripheral edge position protrusion ratio LT / LC is set to a value in the range greater than 0 and less than 0.5. That is, in a cross section of the blade 7 when the blade 7 is cut by the reference imaginary cylindrical surface Q, the protrusion leading edge outer end 72c of the blade protrusion portion 72 is located closer to the leading edge 7a of the blade 7 than to the trailing edge 7b of the blade 7.

[0080] In this embodiment, the entire leading edge 72a and the entire trailing edge 72b of the blade protrusion 72 are located closer to the leading edge 7a of the blade 7 than the trailing edge 7b of the blade 7. That is, as shown in Fig. 13, the leading edge 72a and the trailing edge 72b of the blade protrusion 72 are located closer to the leading edge 7a of the blade 7 than the chord center line P. The chord center line P is a line that shows the distribution of the centers of the chord lines of the blade 7 in the radial direction of the boss 6, where the chord line is a straight line connecting the leading edge 7a and the trailing edge 7b of the blade 7 in a cross section of the blade 7 when the blade 7 is cut by an arbitrary imaginary cylindrical plane centered on the axis Z. Other configurations are the same as in the first embodiment.

[0081] In this propeller fan 5 and blower 1, the leading edge 7a of the blade 7 corresponds to the leading edge 71a of the blade main body 71. The leading edge 72a of the blade protrusion 72 is located away from the leading edge 7a of the blade 7 toward the trailing edge 7b of the blade 7. The leading edge 72a of the blade protrusion 72 is formed parallel to the leading edge 7a of the blade 7. Even in this configuration, when each blade 7 rotates integrally with the boss 6, airflow turbulence can be generated behind the blade protrusion 72 in the rotation direction W of the boss 6, and the expansion of the separation of the airflow that separates from the blade 7 at the leading edge 72a of the blade protrusion 72 can be suppressed. This reduces noise caused by the leading-edge separation vortex 10 and the wake vortex 11, and more reliably reduces noise when each blade 7 rotates integrally with the boss 6.

[0082] Furthermore, the position of the protrusion leading edge outer end 72c in the cross section of the blade 7 when the blade 7 is cut by the reference imaginary cylindrical plane Q is closer to the leading edge 7a of the blade 7 than to the trailing edge 7b of the blade 7. Therefore, the outer peripheral edge position protrusion ratio LT / LC can be set to a value smaller than 0.5, and as can be seen from Figure 15, noise generated when each blade 7 rotates integrally with the boss 6 can be further reliably reduced.

[0083] 15, even if the outer peripheral projection ratio LT / LC is not less than 0.5, a significant noise reduction effect can be obtained as long as the outer peripheral projection ratio LT / LC is in the range of 0.65 or less. Therefore, it is sufficient for the outer peripheral projection ratio LT / LC to be set to a value in the range of 0 or more and 0.65 or less.

[0084] Furthermore, in the second embodiment, the distance between the leading edge 7a of the blade 7 and the leading edge 72a of the blade protrusion 72 in the rotation direction of the boss 6 may be set to be equal to or greater than the protrusion outer peripheral edge length Lt3. In this way, when the blade protrusion 72 is formed by pressing the raw material plate, it is possible to prevent the leading edge 7a of the blade 7 from being deformed in accordance with the plastic deformation of the raw material plate that accompanies the formation of the blade protrusion 72.

[0085] Embodiment 3 FIG. 16 is a plan view showing a main part of a propeller fan in a blower according to the third embodiment. FIG. 16 is a view corresponding to FIG. 4 in the first embodiment. In the blade protrusion 72, the angle formed between the leading edge 72a of the blade protrusion 72 and the outer peripheral edge 72g of the blade protrusion 72 at the protrusion leading edge outer end 72c is defined as a first protrusion interior angle α1. In the blade protrusion 72, the angle formed between the leading edge 72a of the blade protrusion 72 and the inner peripheral edge 72h of the blade protrusion 72 at the protrusion leading edge inner end 72d is defined as a second protrusion interior angle α2. In this embodiment, both the first protrusion interior angle α1 and the second protrusion interior angle α2 of the blade protrusion 72 are right angles. The other configurations are the same as those in the first embodiment.

[0086] Even in this case, when each blade 7 rotates integrally with the boss 6, turbulence in the airflow can be generated behind the blade protrusion 72 in the rotation direction W of the boss 6, and separation of the airflow from the blade 7 at the leading edge 72a of the blade protrusion 72 can be suppressed. This makes it possible to more reliably reduce noise when each blade 7 rotates integrally with the boss 6.

[0087] In the third embodiment, the blade 7 of the first embodiment has a configuration in which the first and second protrusion interior angles α1 and α2 of the blade protrusion 72 are both right angles. However, a configuration in which the first and second protrusion interior angles α1 and α2 of the blade protrusion 72 are both right angles may also be applied to the blade 7 of the second embodiment. This configuration can also prevent the airflow from separating from the blade 7 at the leading edge 72a of the blade protrusion 72, and more reliably reduce noise when each blade 7 rotates integrally with the boss 6.

[0088] Embodiment 4 FIG. 17 is a plan view showing a main part of a propeller fan in a blower according to embodiment 4. FIG. 17 is a view corresponding to FIG. 4 in embodiment 1. In this embodiment, the first protrusion interior angle α1 and the second protrusion interior angle α2 of the blade protrusion 72 are both acute angles. As a result, in this embodiment, the protrusion leading edge length Lt1, which is the length of the leading edge 72a of the blade protrusion 72, is longer than the protrusion trailing edge length Lt2, which is the length of the trailing edge 72b of the blade protrusion 72. The other configurations are the same as those in embodiment 1.

[0089] Even in this case, when each blade 7 rotates integrally with the boss 6, turbulence in the airflow can be generated behind the blade protrusion 72 in the rotation direction W of the boss 6, and separation of the airflow from the blade 7 at the leading edge 72a of the blade protrusion 72 can be suppressed. This makes it possible to more reliably reduce noise when each blade 7 rotates integrally with the boss 6.

[0090] In the fourth embodiment, the blade 7 of the first embodiment has a configuration in which the first and second protrusion interior angles α1 and α2 of the blade protrusion 72 are both acute angles. However, the blade 7 of the second embodiment may have a configuration in which the first and second protrusion interior angles α1 and α2 of the blade protrusion 72 are both acute angles. This configuration can also be applied to the blade 7 of the second embodiment. This configuration can prevent the airflow from separating from the blade 7 at the leading edge 72a of the blade protrusion 72, and more reliably reduce noise when each blade 7 rotates integrally with the boss 6.

[0091] Here, the noise generated by the fans 1 according to each of the first, third, and fourth embodiments was compared with the noise generated by the fans of the comparative example. Fig. 18 is a graph showing the noise reduction values ​​[dB] of the fans 1 according to each of the first, third, and fourth embodiments.

[0092] 18, it can be seen that the noise generated by the fans 1 according to each of the first, third, and fourth embodiments is all reduced compared to the noise generated by the fan of the comparative example. Furthermore, the noise reduction value of the fans 1 according to each of the first, third, and fourth embodiments is all greater than −0.5 dB. Therefore, noise reduction is stably achieved in each of the fans 1 according to each of the first, third, and fourth embodiments.

[0093] In the third embodiment, the first and second protrusion interior angles α1 and α2 of the wing protrusion 72 are both right angles. In the fourth embodiment, the first and second protrusion interior angles α1 and α2 of the wing protrusion 72 are both acute angles. Therefore, by making the first and second protrusion interior angles α1 and α2 of the wing protrusion 72 both equal to or smaller than a right angle, it is possible to more reliably reduce noise when each blade 7 rotates integrally with the boss 6.

[0094] Furthermore, noise reduction is stably achieved in all of the blowers 1 according to the first, third, and fourth embodiments. This shows that there is an improved degree of freedom in the shape of the blade protrusions 72 in the propeller fan 5. Therefore, even if the shape of the blade protrusions 72 in the propeller fan 5 is changed to a shape that is easier to manufacture, or even if the shape of the blade protrusions 72 of some of the propeller fans 5 deviates from the target shape due to variations in manufacturing precision, noise reduction can be more reliably achieved.

[0095] Furthermore, the relationship between the leading edge length ratio Lt1 / LZ and the noise reduction value in any of the second to fourth embodiments is similar to the result shown in Fig. 12 for the first embodiment. Therefore, in each of the second to fourth embodiments, by setting the leading edge length ratio Lt1 / LZ to a range of 0.045 or more, a significant noise reduction effect can be obtained.

[0096] Furthermore, the relationship between the projection thickness ratio tt / t and the noise reduction value in embodiment 2 is similar to the result shown in Fig. 11 for embodiment 1. Therefore, in embodiment 2 as well, by setting the projection thickness ratio tt / t in the range of 0.42 or more and 5.1 or less, a significant noise reduction effect can be achieved.

[0097] In each of the above embodiments, the blade main body 71 is fixed to the spider section 62 with the spider section 62 overlapping the blade suction surface 9. However, this is not limited to this, and the blade main body 71 may be fixed to the spider section 62 with the spider section 62 overlapping the blade pressure surface 8. In each of the above embodiments, the boss 6 may be cylindrical, and the blade main body 71 may be fixed to the cylindrical outer peripheral surface of the boss 6. Furthermore, in each of the above embodiments, the boss 6 and each of the bosses 7 may be formed integrally.

[0098] The configurations described in the above embodiments are merely examples of the contents of the present disclosure. The embodiments can be combined with other known technologies. Part of the configuration of the embodiments can be omitted or modified without departing from the gist of the present disclosure.

[0099] Examples of aspects that may be included in the present disclosure are set forth below as appendices. (Appendix 1) a boss that is rotatable around an axis; a plurality of blades fixed to the outer periphery of the boss and rotatable integrally with the boss around the axis; Equipped with each of the blades has a blade pressure surface facing a pressure side, which is a front side of the blade in the rotation direction of the boss, and a blade suction surface facing a suction side, which is a rear side of the blade in the rotation direction of the boss, Each of the wings has a wing main body portion fixed to the boss and a wing protrusion portion connected to the wing main body portion, the blade suction surface includes a suction main body surface formed on the blade main body portion, and a suction protrusion surface formed on the blade protrusion portion, protruding from the suction main body surface toward the suction side, the blade pressure surface has a pressure main body surface formed on the blade main body portion and a pressure recessed surface formed on the blade protrusion portion and recessed with respect to the pressure main body surface, of the leading edge and the trailing edge of the blade in the rotation direction of the boss, the trailing edge of the blade is the trailing edge of the blade main body in the rotation direction of the boss, A propeller fan, wherein, of the leading edge and trailing edge of the blade protrusion in the rotation direction of the boss, the trailing edge of the blade protrusion is located at a position away from the trailing edge of the blade toward the leading edge of the blade. (Appendix 2) a leading edge of the wing protrusion and a leading edge of the wing main body are formed continuously as a leading edge of the wing, 2. The propeller fan according to claim 1, wherein the leading edge of the blade has a shape such that the leading edge of the blade protrusion protrudes toward the negative pressure side relative to the leading edge of the blade main body, and the leading edge of the blade protrusion is recessed toward the pressure side relative to the leading edge of the blade main body. (Appendix 3) the leading edge of the blade is the leading edge of the blade main body in the rotation direction of the boss, a leading edge of the wing protrusion is located at a position away from the leading edge of the wing toward the trailing edge of the wing, 2. The propeller fan according to claim 1, wherein the leading edge of the blade protrusion is formed parallel to the leading edge of the blade. (Appendix 4) Of both ends of the leading edge of the wing protrusion, the end located outward in the radial direction of the boss is the protrusion leading edge outer end, a reference chord length is a linear distance from the leading edge of the blade to the trailing edge of the blade in a cross section of the blade when the blade is cut by a reference imaginary cylindrical plane that passes through the outer end of the leading edge of the projection and has the axis as its center; When the blade is cut by the reference imaginary cylindrical surface, the linear distance from the leading edge of the blade to the outer end of the leading edge of the protrusion is defined as a first protrusion distance. 2. The propeller fan according to claim 1, wherein the ratio of the first protrusion distance to the reference chord length is a value in the range of 0 to 0.65. (Appendix 5) 5. The propeller fan according to claim 4, wherein a position of an outer end portion of the leading edge of the protrusion in a cross section of the blade when the blade is cut by the reference imaginary cylindrical plane is closer to a leading edge of the blade than to a trailing edge of the blade. (Appendix 6) Of both ends of the leading edge of the wing protrusion, the end located radially inward of the boss is a protrusion leading edge inner end, Of both ends of the leading edge of the wing protrusion, the end located outward in the radial direction of the boss is the protrusion leading edge outer end, The inner peripheral edge of the wing protrusion is connected to the inner end of the protrusion leading edge, The outer peripheral edge of the wing protrusion is connected to the outer end of the protrusion leading edge, 6. The propeller fan according to any one of claims 1 to 5, wherein the angle formed between the leading edge of the blade protrusion and the outer peripheral edge of the blade protrusion at the protrusion leading edge outer end, and the angle formed between the leading edge of the blade protrusion and the inner peripheral edge of the blade protrusion at the protrusion leading edge inner end are both equal to or smaller than a right angle. (Appendix 7) 7. The propeller fan according to claim 1, wherein a length of a leading edge of the blade protrusion is longer than a length of a trailing edge of the blade protrusion. (Appendix 8) the wing protrusion has an offset portion and a connecting portion connecting an outer periphery of the offset portion and the wing main body portion to each other, the offset portion is disposed so as to be shifted with respect to the blade main body portion in a direction in which the negative pressure protrusion surface protrudes toward the negative pressure side relative to the negative pressure main body surface, If the thickness of the offset portion is defined as a protrusion thickness, and the distance by which the offset portion is shifted relative to the blade main body toward the suction side of the blade is defined as a protrusion height, then: 8. The propeller fan according to claim 1, wherein a ratio of the height of the protrusion to the thickness of the protrusion is set in a range of 0.42 to 5.1. (Appendix 9) the boss has a boss main body and a plurality of blade fixing portions protruding from an outer periphery of the boss main body, The wing main body portions of the plurality of wings are individually fixed to the plurality of wing fixing portions, The propeller fan according to any one of Supplementary notes 1 to 8, wherein the thickness of each of the blade fixing portions is greater than the thickness of the blade main body portion. (Appendix 10) A cylindrical bell mouth and the propeller fan according to any one of Supplementary Note 1 to Supplementary Note 9, which is arranged inside the bell mouth; and A blower equipped with: [Explanation of symbols]

[0100] 1 blower, 3 bell mouth, 5 propeller fan, 6 boss, 7 blade, 8 blade pressure surface, 9 blade suction surface, 61 boss main body, 62 spider part (blade fixing part), 71 blade main body, 72 blade protrusion part, 81 pressure main body surface, 82 pressure recess surface, 91 suction main body surface, 92 suction protrusion surface, 7a leading edge, 7b trailing edge, 71a leading edge, 71b trailing edge, 72a leading edge, 72b trailing edge, 72c protrusion leading edge outer end, 72d protrusion leading edge inner end, 72g outer peripheral edge, 72h inner peripheral edge, 721 offset part, 722 connecting part.

Claims

1. a boss that is rotatable around an axis; a plurality of blades fixed to the outer periphery of the boss and rotatable integrally with the boss around the axis; Equipped with each of the blades has a blade pressure surface facing a pressure side, which is a front side of the blade in the rotation direction of the boss, and a blade suction surface facing a suction side, which is a rear side of the blade in the rotation direction of the boss, Each of the wings has a wing main body portion fixed to the boss and a wing protrusion portion connected to the wing main body portion, the blade suction surface includes a suction main body surface formed on the blade main body portion, and a suction protrusion surface formed on the blade protrusion portion, protruding from the suction main body surface toward the suction side, the blade pressure surface has a pressure main body surface formed on the blade main body portion and a pressure recessed surface formed on the blade protrusion portion and recessed with respect to the pressure main body surface, of the leading edge and the trailing edge of the blade in the rotation direction of the boss, the trailing edge of the blade is the trailing edge of the blade main body in the rotation direction of the boss, A propeller fan, wherein, of the leading edge and trailing edge of the blade protrusion in the rotation direction of the boss, the trailing edge of the blade protrusion is located at a position away from the trailing edge of the blade toward the leading edge of the blade.

2. a leading edge of the wing protrusion and a leading edge of the wing main body are formed continuously as a leading edge of the wing, 2. The propeller fan according to claim 1, wherein the leading edge of the blade is shaped such that the leading edge of the blade protrusion protrudes toward the negative pressure side relative to the leading edge of the blade main body, and the leading edge of the blade protrusion is recessed toward the pressure side relative to the leading edge of the blade main body.

3. the leading edge of the blade is the leading edge of the blade main body in the rotation direction of the boss, a leading edge of the wing protrusion is located at a position away from the leading edge of the wing toward the trailing edge of the wing, The propeller fan according to claim 1 , wherein the leading edges of the blade protrusions are formed parallel to the leading edges of the blades.

4. Of both ends of the leading edge of the wing protrusion, the end located outward in the radial direction of the boss is the protrusion leading edge outer end, a reference chord length is a linear distance from the leading edge of the blade to the trailing edge of the blade in a cross section of the blade when the blade is cut by a reference imaginary cylindrical plane that passes through the outer end of the leading edge of the projection and has the axis as its center; When the blade is cut by the reference imaginary cylindrical plane, a linear distance from the leading edge of the blade to the outer end of the leading edge of the protrusion is defined as a first protrusion distance. The propeller fan according to claim 1 , wherein the ratio of the first projection distance to the reference blade chord length is a value in the range of 0 to 0.

65.

5. 5. The propeller fan according to claim 4, wherein a position of the outer end of the leading edge of the protrusion in a cross section of the blade when the blade is cut by the reference imaginary cylindrical plane is closer to the leading edge of the blade than to the trailing edge of the blade.

6. Of both ends of the leading edge of the wing protrusion, the end located radially inward of the boss is a protrusion leading edge inner end, Of both ends of the leading edge of the wing protrusion, the end located outward in the radial direction of the boss is the protrusion leading edge outer end, The inner peripheral edge of the wing protrusion is connected to the inner end of the protrusion leading edge, The outer peripheral edge of the wing protrusion is connected to the outer end of the protrusion leading edge, 6. A propeller fan according to claim 1, wherein the angle formed between the leading edge of the blade protrusion and the outer peripheral edge of the blade protrusion at the outer end of the protrusion leading edge, and the angle formed between the leading edge of the blade protrusion and the inner peripheral edge of the blade protrusion at the inner end of the protrusion leading edge, are both equal to or smaller than a right angle.

7. The propeller fan according to any one of claims 1 to 5, wherein a length of a leading edge of the blade protrusion is longer than a length of a trailing edge of the blade protrusion.

8. The blade has a constant thickness, the wing protrusion has an offset portion and a connecting portion connecting an outer periphery of the offset portion and the wing main body portion to each other, the offset portion is disposed so as to be shifted with respect to the blade main body portion in a direction in which the negative pressure protrusion surface protrudes toward the negative pressure side relative to the negative pressure main body surface, If the thickness of the offset portion is defined as a protrusion thickness, and the distance by which the offset portion is shifted relative to the blade main body toward the suction side of the blade is defined as a protrusion height, then:

6. The propeller fan according to claim 1, wherein a ratio of the height of the protrusion to the thickness of the protrusion is set in a range of 0.42 to 5.

1.

9. the boss has a boss main body and a plurality of blade fixing portions protruding from an outer periphery of the boss main body, The wing main body portions of the plurality of wings are individually fixed to the plurality of wing fixing portions, The propeller fan according to claim 1 , wherein the thickness of each of the blade fixing portions is greater than the thickness of the blade main body portion.

10. A cylindrical bell mouth and The propeller fan according to any one of claims 1 to 5, which is disposed inside the bell mouth; A blower equipped with:

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