Centrifugal fan
A centrifugal fan includes a spiral housing, a driving mechanism and multiple internally mounted impellers. The driving mechanism and the centrifugal impeller, rotated by the driving mechanism, are installed in the spiral housing. A spiral flow channel is defined between the centrifugal impeller and the spiral housing. When the centrifugal impeller rotates, airflow is sucked axially into the spiral housing through an inlet opening and moves along each blade of the centrifugal impeller into the spiral flow channel. The centrifugal impeller includes a hub and multiple blades. Each blade is secured to the hub at one end and has at least one vertical convex strip or vertical concave strip at an opposite end, wherein the vertical convex strip or vertical concave strip on each of blade disturbs the airflow across thereof and reduces narrow-band noise.
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The present application is based on, and claims priority from, Taiwan Application Serial Number 95114589, filed on Apr. 24, 2006, the disclosure of which is hereby incorporated by reference herein in its entirety.
BACKGROUND1. Field of Invention
The present invention relates to a centrifugal fan. More particularly, the present invention relates to a centrifugal fan with noise reduction functionality.
2. Description of Related Art
As notebook PCs become thinner, less space is available for heat convection and heat dissipation components inside the notebook PC case housing. High-frequency components, such as the CPU (central processing unit) and graphics processing chip, also place limitations on heat dissipation designs. Thus, the mainstream method to dissipate heat is forced heat convection via a centrifugal fan.
A centrifugal fan employs a spiral flow channel design to convert dynamic air energy into static pressure so as to overcome the high air flow impedance inside the notebook PC case housing. However, high static pressure generating centrifugal fans face the dual challenge of reducing noise and improving heat dissipation efficiency. Noise can be divided into broadband noise and narrowband noise, wherein narrowband noise is preferably eliminated from a centrifugal fan.
It is therefore an objective of the present invention to provide a centrifugal fan with a noise reduction functionality so as to reduce noise and improve the overall heat dissipation efficiency.
In accordance with the foregoing and other objectives of the present invention, a centrifugal fan includes a spiral housing, a driving mechanism and multiple internally mounted impellers. The driving mechanism and the centrifugal impeller, rotated by the driving mechanism, are installed in the spiral housing. A spiral flow channel exists between the centrifugal impeller and the spiral housing. When the centrifugal impeller rotates, airflow is sucked axially into the spiral housing through an inlet opening and moves along each blade of the centrifugal impeller into the spiral flow channel. The centrifugal impeller includes a hub and multiple blades. Each of the blades is secured to the hub at one end and has at least one vertical convex strip or vertical concave strip at an opposite end, wherein the vertical convex strip or vertical concave strip on each blade disturbs the airflow across thereof and reduces narrow-band noises.
Thus, each blade of the centrifugal fan has a vertical convex strip or a vertical concave strip at an end of the windward side so as to disturb airflows across thereof, thereby decreasing high-frequency and narrow-band noises. Such centrifugal impeller design overcomes a challenge between noise reducing and heat dissipation efficiency improving in a notebook computer.
It is to be understood that both the foregoing general description and the following detailed description are by examples, and are intended to provide further explanation of the invention as claimed.
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings,
Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.
In this preferred embodiment, a width d of the vertical convex strip 205a or the vertical concave strip 205b is approximately equal to the thickness of the blade 206. However, the width d is not a constant value and its optimum value could vary according to the blade length, blade rotation speed, flow channel shape etc, and does not influence the dissipation performance of the centrifugal fan. More than one vertical convex strip 205a or vertical concave strip 205b may be formed on the blade 206 as long as the dissipation performance of the centrifugal fan is not influenced.
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According to the preferred embodiments of the present invention, each blade of the centrifugal fan has a vertical convex strip or a vertical concave strip at the end of the blade, at the windward side so as to disturb the airflow across thereof, thereby decreasing the high-frequency, narrow-band noise. Such a centrifugal impeller design reduces noise and improves heat dissipation efficiency in a notebook PC.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.
Claims
1. A centrifugal fan, comprising:
- a housing, having an inlet opening;
- a driving mechanism mounted in the housing;
- a centrifugal impeller, driven by the driving mechanism, a flow channel is defined between the centrifugal impeller and the housing, the centrifugal impeller comprising: a hub; and multiple blades, each of the multiple blades secured to the hub at one end and having at least one vertical convex strip at an opposite end, when the centrifugal impeller rotates, airflow is sucked axially into the housing through the inlet opening, and moves along each of the multiple blades, wherein the vertical convex strip at each of the multiple blades disturbs the airflow across thereof and reduces narrow-band noises.
2. The centrifugal fan of claim 1, wherein the driving mechanism is a motor.
3. A centrifugal fan, comprising:
- a housing, having an inlet opening;
- a driving mechanism, mounted in the housing;
- a centrifugal impeller, driven by the driving mechanism, a flow channel is defined between the centrifugal impeller and the housing, the centrifugal impeller comprising: a hub; and multiple blades, each of the multiple blades secured to the hub at one end and having at least one vertical concave strip at an opposite end, when the centrifugal impeller rotates, airflow is sucked axially into the housing through the inlet opening, and moves along each of the multiple blades, wherein the vertical concave strip at each of the multiple blades disturbs the airflow across thereof and reduces narrow-band noise.
4. The centrifugal fan of claim 3, wherein the driving mechanism is a motor.
Type: Application
Filed: Jun 30, 2006
Publication Date: Oct 25, 2007
Applicant:
Inventors: Chun-Fa Tseng (Kaohsiung City), Yu-Nien Huang (Chung Li City), Shun-Ta Yu (Taipei City), Cheng-Yu Wang (Hsinchu City)
Application Number: 11/477,371
International Classification: F04D 29/44 (20060101);