Fan

Abstract

A fan includes a fan frame having an upright barrel, a fan blade unit having a fan hub with radial blades, and a driving module formed of a stator, an axle bearing, a core shaft and a rotor for causing rotation of the fan hub with the blades relative to the stator. The stator has a collar affixed to the barrel of the fan frame, radial ribs extending from and spaced around the periphery of the collar, and three-dimensional wings respectively connected to the free ends of the radial ribs each three-dimensional wings having a smoothly arched and radially and axially extending outer surface.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a fan and more specifically, to a high performance fan in which the stator of the driving module is made out of a magnetic powder material and has three-dimensional wings to provide a three-dimensional magnetic path.

2. Description of the Related Art

Following fast development of computer technology, high-speed CPUs (Central Processing Units) have been continuously created. These high-speed CPUs produce much heat during operation. In order to maintain normal operation of a CPU, heat must be quickly carried away from the CPU. Cooler modules are developed for this purpose. A conventional cooler module is known comprising a heat sink and a cooling fan. The heat sink is attached to the CPU of a computer system to absorb heat energy from the CPU and to transfer absorbed heat energy to its radiation fins. The cooling fan is attached to the radiation fins and controlled to cause currents of air toward the radiation fins, thereby dissipating heat from the radiation fins into outside open air.

A cooling fan for cooler module is generally comprised of a support, a fan motor mounted in the support, and a fan blade assembly coupled to the fan motor and rotatable by the fan motor. When an electric current is connected to the windings at the stator of the motor, the rotor of the fan motor is caused to rotate relative to the stator, and therefore the fan blade assembly that is affixed to the rotor is rotated to cause currents of air. The stator is comprised of a stack of silicon steel plates, providing a two-dimensional magnetic path. This two-dimensional magnetic path design leads to a severe magnetic leakage. Further, because the component parts of the motor must be mounted inside the fan hub, the design of the motor is limited to the configuration of the fan hub, and the fan hub must have a certain dimension. Because the fan hub occupies much installation space in the casing of the cooling module, the blades are relatively shortened, resulting in a reduced wind capacity. When a downward blowing type cooling module is installed to dissipate heat from a CPU, the hottest area of the heat sink is at the center area of the radiation fins right below the cooling fan. However, because the fan hub has a certain dimension and is disposed right above the hottest center area of the radiation fins, currents of air are not be directly sent toward the hottest center area of the radiation fins, resulting in low performance of the cooler module. When increasing the speed of the cooling fan to increase the wind capacity, the noise level of the cooling fan will be relatively increased. Adding a thermal pipe can enhance the heat dissipation performance of the cooler module. However, the use of a thermal pipe relatively increases the cost of the cooler module.

The fan hub size is limited by the stator size of the motor. Further, the magnetic loss of a silicon steel plate is indirectly proportional to its silicon content. The magnetic loss of a silicon steel plate reaches the lowest level when its silicon content is at about 6 wt %˜6.5 wt %. However, increasing the silicon content of a silicon steel plate relatively increasing its fragility level. It is difficult to stamp a silicon steel plate having a high fragility level into a thin sheet, so the silicon content of regular silicon steel plates is controlled below 3 wt %. In addition, the magnetic loss will reduce 5˜10 times when silicon steel plates having silicon content 3˜6.5 wt %. Therefore, using a material of low magnetic loss level for the stator of a motor can effectively lower the voltage and energy loss of the motor.

To a fan motor, it is quite important by using a material of low magnetic loss level to maintain the magnetic properties. Enhancing the magnetic properties of the stator of a fan motor can obtain a relatively greater torsional force under the same working voltage. In addition, to change the design of motor by using a three dimensional magnetic path also can effectively increase the air gap flux density to improve the torsional force. Therefore, the stator size of fan motor can be smaller and relatively reduces the length of the enameled wire to lower the temperature level resulted from copper loss. Reducing the stator size of fan motor can also reduce the size of the fan hub, so that the length of the fan blades can be relatively increased to improve the wind capacity and the heat dissipation efficiency of the cooler module.

SUMMARY OF THE INVENTION

The present invention has been accomplished under the circumstances in view. According to one aspect of the present invention, the fan is comprised of a fan frame, a fan blade unit and a driving module. The fan frame comprises a base and a barrel perpendicularly extending from the base. The driving module is comprised of a stator, an axle bearing, a core shaft and a rotor. The fan blade unit comprises a fan hub and a plurality of radial blades connected to and equiangularly spaced around the fan hub. According to another aspect of the present invention, the stator comprises a collar sleeved onto the barrel of the fan frame and affixed thereof, a plurality of radial ribs radially extended from and equiangularly spaced around the collar for the winding of a respective winding, and a plurality of three-dimensional wings at the free end of each radial rib. The three-dimensional wing each has a smoothly arched surface radially and axially extending at an outer side. According to still another aspect of the present invention, the stator is made out of a magnetic powder material, providing a three-dimensional magnetic path. Based on the isotropic characteristics of the magnetic powder material to combine with the three-dimensional magnetic path type motor design, the invention establishes a streamlined fan hub shape, reduces the fan hub size, extends the length of fan blades, and improves the performance and torsional force of the driving module, thereby increasing the wind capacity of the fan. When compared to conventional fan designs, a fan made according to the present invention has a relatively lower noise level.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sectional side view of a fan in accordance with the present invention.

FIG. 2 is an elevational view of the stator for the driving module of the fan in accordance with the present invention.

FIG. 3 is a schematic drawing showing the three-dimensional magnetic path of the stator for the driving module of the fan in accordance with the present invention.

FIG. 4 is an elevational view of the stator in accordance with a first embodiment of the present invention.

FIG. 5 is an elevational view of the stator in accordance with a second embodiment of the present invention.

FIG. 6 is an elevational view of the stator in accordance with a third embodiment of the present invention.

FIG. 7 is an elevational view of the stator in accordance with a fourth embodiment of the present invention.

FIG. 8 is a sectional side view of FIG. 7.

FIG. 9 is an elevational assembly view of the fan in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 1, 2 and 9, a fan 2 in accordance with the present invention is shown comprised of a fan frame, a driving module and a fan blade unit. The driving module is comprised of a stator 1, at least one axle bearing 143, a core shaft 22 and at least one rotor 23. The fan frame comprises a base 14 and a barrel 141 perpendicularly extending from the center of one side of the base 14. The fan blade unit is comprised of a fan hub 21 and a plurality of blades 24 radially connected to the fan hub 21. The fan frame secures the fan blade unit and the driving module.

The stator 1 comprises a collar 11, a plurality of three-dimensional wings 13 equiangularly spaced around the collar 11, and a plurality of radial ribs 12 equiangularly spaced around the collar 11 and radially connected between the periphery of the collar 11 and the three-dimensional wings 13. Windings 121 can be directly wound round the radial ribs 12. Unlike a conventional design to set plastic pads on the top and bottom sides of the motor stator before winding of the enameled wire on silicon steel plates, the invention greatly reduces the length of the enameled wire, lowering copper loss and improving motor performance. By means of inserting the barrel 141 through the collar 11, the stator 1 is supported on the base 14 of the fan frame (see FIG. 1). The barrel 141 defines therein an axially extending axle bearing hole 142. The axle bearing 143 is mounted in the axle bearing hole 142 inside the barrel 141.

The fan hub 21 can be shaped like a flat cup. Alternatively, the fan hub 21 can be nose-shaped. The core shaft 22 is perpendicularly affixed to the center of the inner side of the fan hub 21 and mounted in the axle bearing 143 to support the fan blade unit on the fan frame. The rotor 23 is affixed to the inside of the fan hub 21. The blades 24 are affixed to the outside of the fan hub 21.

During installation, the collar 11 is sleeved onto the barrel 141 above the base 14, and then the axle bearing 143 is mounted in the barrel 141, and then the core shaft 22 is affixed to the fan hub 21 and mounted in the axle bearing 143 to support the fan blade unit on the fan frame, allowing rotation of the core shaft 22 with the fan blade unit in the axle bearing 143. Further, before installation of the collar 11, the windings 121 are wound round the radial ribs 12. When an electric current is applied to the windings 121, the collar 11 define with the radial ribs 12 and the wings 13 a three-dimensional magnetic path for enabling the windings 121 to induce with the rotor 23, thereby causing a magnetic repulsive force to rotate the rotor 23 relative to the stator 1, and therefore the fan blade unit is rotated with the rotor 23 and the core shaft 22 relative to the stator 1 and the fan frame.

The collar 11, the radial ribs 12 and the wings 13 of the stator 1 are made in integrity by means of powder metallurgy, mechanical processing or casting. Alternatively, The collar 11, the radial ribs 12 and the wings 13 can be separately made, and then fastened together by a bonding technique, welding technique, riveting, screw joint or plug joint. Further, by means of the three-dimensional magnetic path design of the stator 1, different magnetic materials may be selectively used to determine the magnetic characteristic of the stator 1, thereby improving the speed when the rotor 23 is caused to rotate by the stator 1, and therefore the driving efficiency and torsional force of the driving module can be greatly improved. The magnetic materials can be soft magnetic metal materials (Fe, Ni, Si, Co, etc.) or ferromagnetic materials (MO—Fe₂0₃, MO-6Fe₂0₃, MM '0₃, etc.). Further, by means of the collar 11, the stator 1 is directly coupled to the axle bearing 143.

Further, the radial ribs 12 of the stator 1 can be made in the shape of a straight bar or cross, or having a star-shaped cross section. The radial ribs 12 can also be made having a solid structure, and stepped configuration. Further, the collar 11 of the stator 1 can be formed integral with the barrel 141 of the fan frame.

Further, the wings 13 are based on a three-dimensional design. The outer surface of each wing 13 is a curved surface that curves smoothly in axial direction as well as radial direction. The rotor 23 is a magnet that can be shaped like a hollow cylinder. Alternatively, the rotor 23 can be made having a curved inner surface that fits the curvature of the curved outer surface of each wing 13. The fan hub 21 can be shaped like a flat cup. Alternatively, the fan hub 21 can be nose-shaped to reduce the dimension so that the blades 24 can be made relatively longer to provide a relatively greater wind capacity for enabling outside cooling air to be directly guided into the hottest center area right beneath the fan hub 21 to enhance the heat dissipation efficiency. Therefore, under a same heat dissipation efficiency, the speed of the fan 2 can be relatively reduced, lowering the noise level and the power consumption.

FIGS. 3A and 3B illustrate the three-dimensional magnetic path of the stator of the driving module. FIG. 3A shows co-existence of four magnetic flux loops during rotation of the rotor. For instance, magnetic flux flows from the rotor 23 toward one wing 13, and then flows radially from the wing 13 to the associating radial rib 12, and then flows from the radial rib 12 to the collar 11, and then flows along the periphery of the collar 11 to another radial rib 12, and then flows back to the wing 13 and then the rotor 23, forming one magnetic flux loop. Therefore, two magnetic paths are bilaterally extending over one radial rib 12, and the two magnetic paths at each radial rib 12 extend in reversed directions along the collar 11 toward another two radial ribs 12 for further circulation. FIG. 3B illustrates the magnetic path at one side of one wing. The magnetic flux flows from the rotor 23 toward the wing 13 and then the associating radial rib 12. Because the surface area of the wing 13 is greater than the lateral area of the stacked silicon steel plates in a conventional fan structure, much magnetic flux is allowed to pass, thereby improving the performance of the motor.

The shape of the stator 1 shown in FIG. 2 is obtained subject to a computer digital simulation to calculate the three-dimensional magnetic path and the motor performance. This model has been examined by means of a test, and the test result shows that the diameter of the silicon steel plates of the motor can be reduced from the original design of 24 mm to 21.6 mm, i.e., the motor diameter can be reduced by 10%; the fan hub diameter can be reduced from the original design of 32.77 mm to 29.35 mm; the fan speed can be increased from the original design of 2500 rpm to 3000 rpm. Therefore, the invention greatly reduces the profile of the driving device, and increases the size of the blades to increase the wind capacity.

FIG. 4 is an elevational view of the stator in accordance with the first embodiment of the present invention. The stator 1 may be variously shaped. FIG. 5 is an elevational view of a stator for fan in accordance with a second embodiment of the present invention. FIG. 6 is an elevational view of a stator for fan in accordance with a third embodiment of the present invention. FIG. 7 is an elevational view of a stator for fan in accordance with a fourth embodiment of the present invention. FIG. 8 is a sectional side view of the stator in accordance with the fourth embodiment of the present invention. According to the first embodiment of the present invention, each wing 13 of the stator 1 has a smoothly arched outer surface, and each radial rib 12 extends perpendicular from the flat inner surface of the associating wing 13 (see FIG. 4). According to the second embodiment of the present invention, the wings 13 have a transverse width relatively greater than the transverse width of the radial ribs 12 (see FIG. 5). According to the first and second embodiments of the present invention, the upper part of each wing 13 above the elevation of the associating radial rib 12 has a vertical height greater than the vertical height of the lower part of each wing 13 below the elevation of the associating radial rib 12 (see FIGS. 4 and 5). According to the third and fourth embodiments of the present invention, each wing 13 has a transverse width relatively longer than its vertical height (see FIGS. 6 and 7). According to the fourth embodiment of the present invention, each wing 13 has its bottom side smoothly curved downwardly inwards and suspending below the elevation of the associating radial rid 12 (see FIG. 8).

Further, the fan frame can be made having a part assembled to connect with a circuit board to form a fan control circuit, facilitating mass production.

In conclusion, the invention provides a fan 2 comprised of a fan frame, which comprises a base 14 and a barrel 141 perpendicularly extending from the center of the base 14, a driving module, which comprises a stator 1, at least one axle bearing 143, a core shaft 22 and at least one rotor 23, and a fan blade unit, which comprises a fan hub 21 and a plurality of blades 24 radially connected to the fan hub 21. The stator 1 has a three-dimensional profile. By means of utilizing the isotropic characteristics of a magnetic powder material to combine with a three-dimensional magnetic path type motor design, the invention establishes a streamlined fan hub shape, reduces the fan hub size, extends the length of fan blades, and improves the performance and torsional force of the driving module, thereby increasing the wind capacity of the fan; i.e., by means of the three-dimensional design of the wings 13 of the stator 1 and the smoothly arched profile of the fan hub 21 and the rotor 23, the invention greatly reduces the dimension of the driving module and the size of the fan 2 and extends the length of the blades 24.

By means of the three-dimensional design of the stator 1 to control the magnetic path, the invention greatly improves the speed and torsional force of the driving module (motor).

In actual practice, the fan 2 of the present invention has the following features and advantages:

1. The stator 1 is made out of a magnetic material defining a three-dimensional magnetic path, eliminating magnetic leakage and improving the speed and torsional force of the driving module (motor).

2. Based on the three dimensional design of the wings 13 and radial ribs 12 of the stator 1, the size of the fan hub 21 can be relatively reduced, and the length of the fan blades 24 can be relatively increased to increase the wind capacity of the fan 2.

3. The fan hub 21 matches the smoothly arched shape design of the stator 1 so that outside cooling air is effectively guided to the hot source at the center below the fan hub 21, enhancing the heat dissipating performance.

Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.

Claims

1. A fan comprising: a fan frame, said fan frame comprising a base and a barrel perpendicularly extending from the center of said base;a fan blade unit, said fan blade unit comprising a fan hub and a plurality of blades radially connected to said fan hub;a driving module, said driving module comprising a stator affixed to said barrel of said fan frame, said stator comprising a collar sleeved onto said barrel of said fan frame and a plurality of radial ribs radially extending from and equiangularly spaced around the periphery of said collar for the winding of a respective winding, at least one axle bearing mounted inside said barrel of said fan frame, a core shaft affixed to said fan hub of said fan blade unit and supported in said at least one axle bearing, and at least one rotor affixed to an inner side of said fan hub and spaced around said stator;wherein said stator comprises a plurality of three-dimensional wings respectively connected to the free ends of said radial ribs remote from said collar, said three-dimensional wings each having a smoothly arched surface radially and axially extending at an outer side.

2. The fan as claimed in claim 1, wherein said stator is made out of a magnetic material to provide a three-dimensional magnetic path, said magnetic material being elected from one of the soft magnetic metal materials including Fe, Ni, Si and Co and the ferromagnetic materials including MO—Fe203, MO-6Fe203 and MM '03.

3. The fan as claimed in claim 1, wherein said radial ribs of said stator have the shape of a straight bar.

4. The fan as claimed in claim 1, wherein said radial ribs of said stator have the shape of a cross.

5. The fan as claimed in claim 1, wherein said radial ribs of said stator have a star-shaped cross section.

6. The fan as claimed in claim 1, wherein said fan hub is shaped like a flat cup, having a radially and axially extending smoothly curved outer surface.

7. The fan as claimed in claim 1, wherein said fan hub has a nose-like shape and a radially and axially extending smoothly curved outer surface.

8. The fan as claimed in claim 1, wherein said radial ribs of said stator are solid prism having a stepped cross section.

9. The fan as claimed in claim 1, wherein said stator is made in integrity by means of one of the techniques of powder metallurgy, mechanical processing and casting.

10. The fan as claimed in claim 1, wherein said collar, said radial ribs and said wings of said stator are separately made and fastened together by means of one of bonding technique, welding technique, riveting, screw joint and plug joint

11. The fan as claimed in claim 1, wherein said wings of said stator each have a smoothly arched surface which is composed by different flat surface, curve surface, arched surface and cylindrical surface.

12. The fan as claimed in claim 1, wherein said rotor is formed of an annular magnet, said annular magnet having an inner surface fitting the curvature of the wings of said stator.

13. The fan as claimed in claim 1, wherein said barrel in the center of said fan frame is assembled with a hollow part which is assembled with said stator at the hollow part outside and the bottom of hollow part to connect with a circuit board to form a fan control circuit.

14. The fan as claimed in claim 1, wherein said collar inside of said stator is formed integral with the bearing where the bearing assembled in the center of said fan frame to displace said barrel.