Propeller fan and refrigeration cycle apparatus

Patent metadata

Field	Value
Publication number	US-11333166-B2
Application number	US-201716496544-A
Country	US
Kind code	B2
Filing date	May 25, 2017
Priority date	May 25, 2017
Publication date	May 17, 2022
Grant date	May 17, 2022

Abstract

A propeller fan includes a rotary shaft portion that rotates around an axial center and a plurality of blades disposed around an outer circumferential portion of the rotary shaft portion. Each of the plurality of blades has at least one recessed portion that opens at a trailing edge of the blade. The at least one recessed portion has a first side that is close to an inner circumference of the blade. The first side stretches from the trailing edge toward a leading edge of the blade, and is bent toward an outer circumference of the blade.

First claim

The invention claimed is:

1. A propeller fan, comprising:
a rotary shaft portion configured to rotate around an axial center; and
a plurality of blades disposed around an outer circumferential portion of the rotary shaft portion,
each blade of the plurality of blades having an inner circumferential end, an outer circumferential end, a leading edge stretching from the inner circumferential end to the outer circumferential end, and a trailing edge stretching from the inner circumferential end to the outer circumferential end, and having at least one recessed portion that opens at the trailing edge of the each blade, and
the at least one recessed portion having a first side and a second side that each terminate at the trailing edge, the first side being closer to an inner circumference of the each blade than an outer circumference of the each blade, the first side stretching from the trailing edge toward the leading edge of the each blade and bent toward the outer circumference, the second side being closer to the outer circumference of the each blade than the inner circumference and stretching from the trailing edge toward the leading edge and toward the inner circumference,
in the each blade of the plurality of blades, a second projecting portion being formed in a portion of the trailing edge that is radially inward of the at least one recessed portion and that is closer to the inner circumference than is the at least one recessed portion, the second projecting portion projecting downstream, a first side end of the second projecting portion being closest to the outer circumference, a second side end of the second projecting portion being closest to the inner circumference, the first side end coinciding with a side end of the first side of the at least one recessed portion that terminates at the trailing edge,
the second projecting portion has a curved shape from the first side end to the second side end and including a maximum projection point which is a point of the second projecting portion projecting most downstream of the each blade, the maximum projecting point being located closer to the second side end than the first side end.

2. The propeller fan of claim 1 , wherein, in a top view of the propeller fan, the at least one recessed portion is formed in a substantially triangular shape and including
the first side,
the second side, and
a vertex at which both the first side and the second side terminate at a location that is toward the leading edge.

3. The propeller fan of claim 1 , wherein, in a top view of the propeller fan, the at least one recessed portion is formed in a substantially quadrangular shape and including
the first side,
the second side, and
a third side connecting a side end of the first side that is closest to the leading edge and a side end of the second side that is closest to the leading edge.

4. The propeller fan of claim 1 , wherein a side connecting the first side end of the second projecting portion and the second side end of the second projecting portion along an outer circumference of the second projecting portion forms a fourth side,
a first virtual line being a straight line connecting the first side end and the second side end,
a second virtual line being a line perpendicularly extending to the fourth side from a midpoint of the first virtual line, and
wherein the maximum projection point of the second projecting portion is located closer to the inner circumference than is an intersection of the fourth side and the second virtual line.

5. A refrigeration cycle apparatus, comprising:
a refrigerant circuit in which a compressor, a first heat exchanger, an expansion device, and a second heat exchanger are connected by pipes; and
the propeller fan of claim 1 mounted in a cooling unit together with the first heat exchanger to supply air to the first heat exchanger.

6. A propeller fan, comprising:
a rotary shaft portion configured to rotate around an axial center; and
a plurality of blades disposed around an outer circumferential portion of the rotary shaft portion,
each blade of the plurality of blades having at least one recessed portion that opens at a trailing edge of the each blade, and
the at least one recessed portion having a first side that is closer to an inner circumference of the each blade than an outer circumference of the each blade, the first side stretching from the trailing edge toward a leading edge of the each blade and bent toward the outer circumference,
in the each blade of the plurality of blades, a second projecting portion being formed in a portion of the trailing edge that is closer to the inner circumference than is the at least one recessed portion, the second projecting portion projecting downstream,
wherein, in a top view of the propeller fan viewed from an upstream side in an axial direction, the first side forms an arc that corresponds to a part of a concentric circle that is concentric with the rotary shaft portion.

7. A propeller fan, comprising:
a rotary shaft portion configured to rotate around an axial center; and
a plurality of blades disposed around an outer circumferential portion of the rotary shaft portion,
each blade of the plurality of blades having at least one recessed portion that opens at a trailing edge of the each blade, and
the at least one recessed portion having a first side that is closer to an inner circumference of the each blade than an outer circumference of the each blade, the first side stretching from the trailing edge toward a leading edge of the each blade and bent toward the outer circumference,
in the each blade of the plurality of blades, a second projecting portion being formed in a portion of the trailing edge that is closer to the inner circumference than is the at least one recessed portion, the second projecting portion projecting downstream,
wherein, in the each blade of the plurality of blades, the first side has at least one first projecting portion projecting toward the outer circumference of the each blade.

Assignees

• Mitsubishi Electric Corp

Inventors

• Yamamoto Katsuyuki
• Nakashima Seiji

Classifications

• F04D29/667

  by influencing the flow pattern, e.g. suppression of turbulence · CPC title

• F05D2240/304

  related to the trailing edge of a rotor blade · CPC title

• F05B2240/301

  Cross-section characteristics · CPC title

• F04D29/384 Primary

  characterised by form · CPC title

• F05D2240/303

  related to the leading edge of a rotor blade · CPC title