OIL-CIRCULATING STRUCTURE FOR FAN
An oil-circulating structure for fan comprises an oily bearing with a central axis hole for pivoting a fan shaft. An inner oil-collecting recess trench is formed in the central axis hole of the oily bearing and has an inner thread shape oil-guiding trench set inside. Radial through holes penetrate from two ends of the inner thread shape oil-guiding trench to outside wall of the bearing. An outer oil-collecting recess trench is formed on the outside wall of the bearing and is connected with the inner thread shape oil-guiding trench by means of the radial through holes. When the fan rotates, a lubricant in the inner oil-collecting recess trench is pushed by the rotating fan shaft to flow in-and-out between the outer oil-collecting recess trench and the inner oil-collecting recess trench through the inner thread shape oil-guiding trench and the radial through holes so as to achieve oil-circulation of the oily bearing in which the lubricant won't overflow through the end surface of the oily bearing.
The present invention is relating to a bearing lubricating structure for DC fan without bushing, more particularly to an oil-circulating structure for fan.
BACKGROUND OF THE INVENTIONSince electronic device generates heat during operating, it will damage easily due to overheat without effective heat-dissipation. It is common to install a DC fan without bushing on electronic device for heat-dissipating. The DC fan without bushing has been well known to set various bearing like a ball bearing or an oily bearing between a fan wheel and a fan housing in order to enhance rotation and diminish noise of the fan. The oily bearing has porous structure made by sintering copper alloy or iron alloy so as to absorb a lubricant. However, the lubricant will be pushed to sputter by rotating a fan shaft to contaminate entire the fan housing when the fan shaft in the oily bearing rapidly rotates, and the oil-retaining quantity of the oily bearing decreases and distributes unevenly. Therefore, when the fan is used for a long time, the lubricating efficiency of bearing becomes bad gradually noise of bearing becomes loud gradually, even the fan will stop rotating.
A heat-dissipating fan was disclosed in R.O.C. Taiwan Patent No. 471557 entitled “lubricating oil-circulating structure for fan shaft”, which is composed of a housing, a stator and a rotor. An oily bearing has a bearing body with through holes (i.e. axis holes). A ring portion is extended from one end of the bearing body to form an oil tank. A trench is set on the radial surface of bearing body to make a released lubricant flow to the trench by passing the through holes and return to the oil tank and the through holes by passing the trench. The oil tank is set at the ring portion of the oily bearing and the trench is set on the bearing body, so that the lubricant will flow to the end surface of the oily bearing to reduce oil-retaining quantity resulting in weakening lubricating effect. Besides, since the oil tank and the trench are the shape of a line easy to result in gathering lubricant at one side only, the oil-circulating efficiency of the lubricant becomes worse.
SUMMARYThe primary object of the present invention is to provide an oil-circulating structure for fan. An inner thread shape oil-guiding trench is set in an inner oil-collecting recess trench that is formed in an axis hole of an oily bearing. Radial through holes are separately set at the two ends of the inner thread shape oil-guiding trench and penetrate to an outer oil-collecting recess trench outside the oily bearing to make a lubricant flow in the axis hole following the rotation of fan shaft, then through the radial through holes flow into the outer oil-collecting recess trench without overflowing to end surfaces of the oily bearing so as to perform an internal-recycle oil-circulating efficiency.
According to the oil-circulating structure for fan of the present invention, an oily bearing is set in a fan housing and has a central axis hole for pivoting a fan shaft. An inner oil-collecting recess trench is formed in the axis hole of the bearing and has an inner thread shape oil-guiding trench set inside. Radial through holes penetrate from two ends of the inner thread shape oil-guiding trench to outside wall of the bearing. An outer oil-collecting recess trench is formed on the outside wall of the oily bearing. The radial through holes penetrate the bearing to connect the inner thread shape oil-guiding trench with the outer oil-collecting recess trench. When the fan rotates, a lubricant in the inner oil-collecting recess trench is pushed by the rotating fan shaft to flow to the outer oil-collecting recess trench through the inner thread shape oil-guiding trench and along the radial through holes for avoiding overflowing from the end surface of the oily bearing so as to perform an axis hole internal-recycle oil-circulating of the oily bearing.
DESCRIPTION OF THE DRAWINGS
In relation to the oil-circulating structure for fan in accordance with this invention, referring to
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The above description of embodiments of this invention is intended to be illustrated and not limiting. Other embodiments of this invention will be obvious to those skilled in the art in view of the above disclosure.
Claims
1. An oil-circulating structure for fan comprising a fan hub with a fan shaft, a fan housing and an oily bearing set in the fan housing, the oily bearing having a central axis hole pivoting with the fan shaft, an inner oil-collecting recess trench being formed in the central axis hole of the oily bearing and having an inner thread shape oil-guiding trench set inside, and an outer oil-collecting recess trench being formed on the outside wall of the bearing, a first radial through hole and a second radial through hole connecting the two ends of the inner thread shape oil-guiding trench with the outer oil-collecting recess trench respectively, when the fan hub rotating, a lubricant in the inner thread shape oil-guiding trench being driven by the rotating fan shaft to flow in-and-out the outer oil-collecting recess trench through the first radial through hole and the second radial through hole so as to perform oil-circulation of the oily bearing.
2. The oil-circulating structure for fan in accordance with claim 1, wherein the inner thread shape oil-guiding trench has a left-hand thread shape.
3. The oil-circulating structure for fan in accordance with claim 1, wherein the inner thread shape oil-guiding trench has a right-hand thread shape.
4. The oil-circulating structure for fan in accordance with claim 1, wherein the outer oil-collecting recess trench is an outer thread shape oil-collecting trench.
Type: Application
Filed: Jul 14, 2003
Publication Date: Jan 20, 2005
Inventor: Nien-Lun Li (Taoyuan City)
Application Number: 10/617,714