阅读说明：本技术 螺旋桨式风扇 (Propeller fan ) 是由 寺本拓矢 池田尚史 安达祐介 于 2017-04-28 设计创作，主要内容包括：螺旋桨式风扇具备设置在旋转轴上的轴部和设置在轴部的外周侧且具有前缘及后缘的翼,在前缘及后缘的至少一方形成有缺口,缺口具有张开角为锐角的一对侧缘部、和形成于一对侧缘部之间的底缘部,在底缘部形成有张开角为钝角的至少一个凸部。(the propeller fan includes a shaft portion provided on a rotating shaft, and a blade provided on an outer peripheral side of the shaft portion and having a leading edge and a trailing edge, wherein a notch is formed in at least one of the leading edge and the trailing edge, the notch includes a pair of side edge portions having an acute opening angle, and a bottom edge portion formed between the pair of side edge portions, and at least one protrusion having an obtuse opening angle is formed in the bottom edge portion.)

1. A propeller fan, wherein,

The propeller fan includes:

A shaft portion provided on the rotating shaft; and

A wing provided on an outer peripheral side of the shaft portion and having a leading edge and a trailing edge,

A notch is formed in at least one of the front edge and the rear edge,

The notch has a pair of side edges with acute opening angle and a bottom edge formed between the side edges,

At least one first convex part with an obtuse opening angle is formed at the bottom edge part.

2. The propeller fan of claim 1,

The first projection is located at a central portion of the notch in a radial direction of the wing.

3. Propeller fan according to claim 1 or 2,

The first convex portion is formed of one or more circular arcs.

4. Propeller fan according to one of claims 1 to 3,

Two concave portions disposed on both sides of the notch with the first convex portion therebetween are formed in the notch,

An opening angle of at least one of the two recesses is an obtuse angle.

5. propeller fan according to one of claims 1 to 4,

The first protrusions are formed in a plurality at the bottom edge portion.

6. Propeller fan according to one of claims 1 to 5,

A second convex portion is formed on a side edge portion located on the outer peripheral side of the pair of side edge portions.

Technical Field

The present invention relates to a propeller fan having a notch formed in at least one of a leading edge and a trailing edge of a blade.

background

Patent document 1 describes a blower provided with blades. The front edge of the blade is formed with a serration composed of a plurality of protrusions whose tips are tapered. The projection has two inclined outer edge portions that approach each other as going from the root portion side toward the tip end side, and a tip end side outer edge portion that connects the two inclined outer edge portions to each other on the tip end side of the projection. The two inclined outer edge portions form an acute angle with each other. The leading end outer edge portion has a shape that suppresses collision of airflows rising toward the negative pressure surface side of the blade. Patent document 1 describes that, according to this configuration, the collision of the airflows rising toward the negative pressure surface side of the blade in the vicinity of the tip of the protrusion can be suppressed, and therefore, the noise can be effectively reduced.

Disclosure of Invention

problems to be solved by the invention

The serration of the blade of patent document 1 has a curved root-side outer edge portion smoothly connecting the oblique outer edge portions to each other on the root side of two projections adjacent to each other. Two inclined outer edge portions adjacent to each other with the root-side outer edge portion therebetween form an acute angle. In such a structure, stress generated by rotation of the blade locally increases at the outer edge portion on the root side, and thus there is a problem that the strength of the blade decreases.

The present invention has been made to solve the above-described problems, and an object thereof is to provide a propeller fan capable of reducing noise and improving strength of blades.

Means for solving the problems

The propeller fan of the present invention includes: a shaft portion provided on the rotating shaft; and a blade provided on an outer peripheral side of the shaft portion, the blade having a leading edge and a trailing edge, a notch being formed in at least one of the leading edge and the trailing edge, the notch having a pair of side edge portions having an acute opening angle and a bottom edge portion formed between the pair of side edge portions, and at least one first protrusion having an obtuse opening angle being formed in the bottom edge portion.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, the portion in which stress concentration occurs in the notch of the blade can be dispersed between the first convex portion and the two concave portions formed with the first convex portion interposed therebetween. Further, since the opening angle of the convex portion is an obtuse angle, an increase in stress in each of the convex portion and the two concave portions can be alleviated. Therefore, the strength of the blade can be improved while maintaining the noise reduction effect due to the provision of the notch in the blade.

Drawings

Fig. 1 is a front view showing a schematic configuration of a propeller fan according to embodiment 1 of the present invention.

fig. 2 is an enlarged view of the notch 30 of the propeller fan according to embodiment 1 of the present invention.

Fig. 3 is an enlarged view of a part III of fig. 1.

Fig. 4 is an enlarged view of a part of a leading edge of a propeller fan according to a comparative example.

Fig. 5 is an enlarged view of the V portion of fig. 1.

Fig. 6 is a front view showing a schematic configuration of a propeller fan according to embodiment 2 of the present invention.

Fig. 7 is an enlarged view of section VII in fig. 6.

Fig. 8 is a front view showing a schematic configuration of a propeller fan according to embodiment 3 of the present invention.

Fig. 9 is an enlarged view of the IX portion of fig. 8.

Fig. 10 is a front view showing a schematic configuration of a propeller fan according to embodiment 4 of the present invention.

Fig. 11 is an enlarged view of a portion XI of fig. 10.

Fig. 12 is a front view showing a schematic configuration of a propeller fan according to embodiment 5 of the present invention.

Fig. 13 is an enlarged view of XIII part in fig. 12.

Fig. 14 is a front view showing a schematic configuration of a propeller fan according to embodiment 6 of the present invention.

fig. 15 is an enlarged view of the XV portion of fig. 14.

Fig. 16 is a front view showing a schematic configuration of a propeller fan according to embodiment 7 of the present invention.

Fig. 17 is an enlarged view of the XVII portion in fig. 16.

Detailed Description