Patent Application
20220136521
The present invention relates to the field of heat-dissipating fan and more particularly, to a blade wheel structure for axial fan that enables largely increased air pressure and reduced noise when the fan operates.
Noise and low air pressure occurred during fan operation have long been two of many problems that need to be solved in the fan technical field. Currently, the problems of noise and low air pressure are generally solved by way of controlling the rotational speed via fan circuit design or changing the fan structure.
It is therefore an important target for those skilled in the art to reduce the noise and increase the air pressure produced by the fan during operation thereof.
To effectively solve the problems of the conventional fan blade, it is a primary object of the present invention to provide a blade wheel structure for axial fan, which enables largely increased air pressure.
Another object of the present invention is to provide a blade wheel structure for axial fan, which largely reduces the noise produced during fan operation.
To achieve the above and other objects, the blade wheel structure for axial fan according to a preferred embodiment of the present invention includes a hub and a plurality of blades circumferentially outward extended from the hub. Each of the blades has a tip portion, which is located at a windward side of the blade and is curved in shape or formed into an obtuse angle.
In the present invention, when the fan operates, air flows will first contact with the tip portions of the blades that are located at the windward side. Since the tip portions are respectively curved in shape or formed into an obtuse angle, air flows contacting with the curved or obtuse angled tip portions will be smoothly guided to below the blades to create a pressurizing effect to obtain largely increased air pressure. In addition, the rounded or obtuse angled design for the tip portions can also create an increased surface action area at the windward side of the blades, which enables evenly pressure distribution over the tip portions to thereby reduce the noise produced during fan operation while increasing the air pressure.
The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiment and the accompanying drawings, wherein
The present invention will now be described with a preferred embodiment thereof and by referring to the accompanying drawings.
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More specifically, the hub 20 has a center point 200 defined in a central area thereof. A radius from the center point 200 to a circumference of the hub 20 defines a first pitch circle 3; a second pitch circle 4 concentric with the first pitch circle 3 is defined at an outer side of the first pitch circle 3 with a first radial distance D1 spaced between them; and a third pitch circle 5 concentric with the first pitch circle 3 is defined at an outer side of the first pitch circle 3 with a second radial distance D2 spaced between them. It is noted the third pitch circle 5 just passes outmost edges of the blades 21, and the first radial distance D1 is from 0.1 to 0.9 times of the radius of the first pitch circle 3. However, in the illustrated embodiment according to the present invention, there is not any particular limitation to a ratio of the first radial distance D1 to the second radial distance D2, and a user may adjust this ratio according to actual requirement in use.
Each of the tip portions 210 further includes a first arc 2100 and a second arc 2101. The first arc 2100 is extended from a point, at where the tip portion 210 meets the second pitch circle 4, to the third pitch circle 5; and the second arc 2101 is extended from another point, at where the tip portion 210 meets the first pitch circle 3, to the second pitch circle 4.
In the present invention, when the fan operates, air flows will first reach at the tip portions 210 of the blades 20 that are located at the windward side. Since the tip portions 210 are respectively curved in shape or formed into an obtuse angle, air flows contacting with the curved or obtuse angled tip portions 210 will be smoothly guided to below the blades 21 to create a pressurizing effect to obtain largely increased air flow pressure. In addition, the rounded or obtuse angled design for the tip portions 210 can also create an increased surface action area at the windward side of the blades 20, which enables evenly pressure distribution over the tip portions 210 to thereby reduce the noise produced during fan operation.
Compared to the conventional fan blade 10, the blade 21 according to the present invention has the following advantages: (1) creating largely increased air pressure; and (2) largely reducing the noise produced during fan operation.
The present invention has been described with a preferred embodiment thereof and it is understood that many changes and modifications in the described embodiment can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims.
