Daikin Industries, Ltd.

Tooru Iwata

Hirotaka Tomioka

Kaname Maruyama

Takahiro Yamasaki

Akira Komatsu

Kazuyasu Matsui

Shimei Tei

Zuozhou Chen

Anan Takada

Tomohiro Ishibashi

Shigeyuki Takaoka

A propeller fan includes a hub rotatable about an axis, and a plurality of blades extending radially outward from an outer peripheral surface of the hub. A ring surrounds the plurality of blades and is connected to each blade tip. A maximum camber location is on a camber line where a distance from a chord line to the camber line in an arc-shaped cross section of each blade about the axis is maximum. An axial height is from a trailing edge to the camber line in a direction along the axis. Each blade has a first portion provided inside in the radial direction of rotation and whose axial height at the maximum camber location is substantially constant, and a second portion provided outside in the radial direction of rotation and whose axial height at the maximum camber location increases toward the blade tip.

Propeller fan

Blades (to) of a propeller fan () have different circumferential pitches &#x3c6;, and &#x3c6;. The blades (to) have different masses so that the center of gravity of the propeller fan () is positioned on a rotational center axis () of the propeller fan (). Blade body portions () of the blades (to) have different thicknesses. In contrast, camber lines of the blades (to) in blade cross section have the same shape, projections of the blades (to) on a plane perpendicular to the rotational center axis () of the propeller fan () have the same shape, and leading edge portions (to) of the blades (to) have the same shape. As a result, a propeller fan () having reduced noise and vibrations can be achieved.

In a blade of a propeller fan, a position on a chord line where the camber becomes maximum is set as a maximum camber position A, and a ratio of a distance d between a leading edge and the maximum camber position A to a chord length c is set as a maximum camber position ratio. The end portion on the hub side of the blade is set as a blade root, and the end portion on the outer circumferential side of the blade is set as a blade end. In the blade, the maximum camber position ratio monotonically increases in the direction from the reference blade cross section located between the blade root and the blade end toward the blade end and becomes maximum at the blade end. Thus, fan efficiency of the propeller fan is improved.

In a blade of a propeller fan, an inclination angle (&#x3c6;) is made by a straight line passing through an outer circumferential side end and an inner circumferential side end of a radial cross section of the blade with a second plane orthogonal to a center axis of a hub. In a blade end of the blade, one end in front of the other end viewed in the rotation direction of the propeller fan is a leading blade end, while the other end behind the leading blade end is a trailing blade end. The blade is shaped such that the inclination angle (&#x3c6;) monotonically increases, in the direction from the intermediate position toward the trailing blade end, in an area extending from an intermediate position between the leading blade end and the trailing blade end to the trailing blade end.

A propeller fan includes a rotary blade hub driven in rotation about a rotation axis, and a rotary blade installed at an outer periphery of the rotary blade hub. The rotary blade includes a rotary blade body protruding from an outer peripheral surface of the rotary blade hub, and a rib formed on an outer peripheral edge portion of a pressure surface of the rotary blade body so as to extend along an outer peripheral edge of the rotary blade body.

Propeller fan and blower unit

A multi-blade centrifugal fan for preventing circular flows in the end portions of an impeller in the axial direction is provided in a simple structure. The multi-blade centrifugal fan is formed of a fan casing of a scroll type and a multi-blade centrifugal impeller. The fan casing has a bellmouth which becomes an air intake. The multi-blade centrifugal impeller has a number of annularly arranged blades inside the fan casing. The centrifugal impeller draws in air through the intake, which faces the bellmouth, and blows out the air in the centrifugal direction through the blades. A retainer ring is provided in an outer peripheral end portion of the impeller. A cylindrical body is integrally provided in such a manner as to extend from the outer end of the retainer ring, so that circular flows toward the intake side are prevented in the end portions of the impeller.

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Osaka, Japan

Tooru Iwata