GB2401488A

GB2401488A - Integrally formed casing/pole plate for a heat-dissipating fan

Info

Publication number: GB2401488A
Application number: GB0310756A
Authority: GB
Inventors: Alex Horng; Yin-Rong Horng; Ching-Sheng Hong
Original assignee: Sunonwealth Electric Machine Industry Co Ltd
Current assignee: Sunonwealth Electric Machine Industry Co Ltd
Priority date: 2003-05-09
Filing date: 2003-05-09
Publication date: 2004-11-10
Also published as: DE20308011U1; GB0310756D0

Abstract

A casing for a heat-dissipating fan includes a bottom board 10a, a plurality of sidewalls 101 extending from the bottom board 10a and magnetic pole faces 13 integrally formed by punching a magnetically conductive plate 1. Stator coil assembly 20 is mounted on base 12. An axial hole 141 is defined in the base 12 of the bottom board 10a, and a bearing 142 is mounted in the axial hole 141 for rotatably holding a shaft 31 of a rotor 30. The magnetic pole faces 13 surround the axial hole 141 and are adjacent to the coil assembly 20 of the stator. Groove 121 receives the lead 41 of the Hall sensor 42 which mounts in aperture 131. Axial and radial fan embodiments are disclosed and the poles may been notched 132 to assist starting. The rotor is axially retained by a circlip adjacent a thrust plate.

Description

240 1 488

INTEGRALLY FORMED CASING FOR A HEAT-DISSIPATING FAN

BACKGROUND OF THE INVENTION

l. Field of the Invention

The present invention relates to an integrally formed casing for a heat s dissipating fan. In particular, the present invention relates to a heatdissipating tan casing that is integrally formed by means of punching a magnetically conductive plate to reduce the number of parts of the casing and the stator, to reduce an overall thickness, and to simplify the structure of the heat-dissipating fan.

l () 2. Description of Related Art

Fig. 8 of the drawings illustrates a conventional heat-dissipating fan with an axial winding. The heat-dissipating fan includes a casing 10, a coil assembly 20, a rotor 3O, a circuit board 40, a metal axle tube 50, an upper pole plate 60, and a lower pole plate 60. The casing 10 includes a plurality of ribs 11 connected to a base 12 on which the metal axle tube 50 is fixed. The circuit board 40 and a bobbin 21 of the coil assembly 20 are mounted around the metal axle tube 50. The upper and lower pole plates 60 are mounted to two sides of the bobbin 21 and each includes a plurality of pole arms that extend to form a plurality of magnetic pole faces. The rotor 30 includes a shaft 31 rotatably 9 extended through a bearing (not shown) mounted in the metal axle tube 50. A change in the polarities of the magnetic pole faces 61 drives the rotor 30 to turn, thereby generating air current by the blades 32 on the rotor 30. However, there are too many parts for the stator (including the coil assembly 20, the bobbin 21, the circuit board 40, the metal axle tube 50, and the upper and lower pole plates 60. The parts of the stator are stacked on the bottom board 10a and thus increase an overall thickness and overall volume of the heat-dissipating fan. As a result, such a heat-dissipating fan cannot be used in notebook type computers as well as other delicate electronic devices.

OBJECTS OF THE INVENTION

The object of the present invention is to provide a heat-dissipating fan casing that is integrally formed by means of punching a magnetically 0 conductive plate to reduce the number of parts of the casing and the stator, to simplify the structure ofthe heat-dissipating fan, and to reduce the manufacture cost.

Another object of the present invention is to a heat-dissipating fan casing that is integrally formed by means of punching a magnetically conductive plate, wherein the base and the magnetic pole faces that are formed by means of punching are used to mount a coil assembly and a circuit board for a stator. Thus, the parts of the stator are not all stacked in an axial direction, thereby reducing the overall thickness of the heat-dissipating fan.

SUMMARY OF THE INVENTION

go lo achieve the aforementioned objects, the present invention provides a casing for a heat-dissipating fan, wherein the casing includes a bottom board and a plurality of sidewalls extending from the bottom board. The bottom board and the sidewalls are integrally formed by means of punching a magnetically conductive plate. The bottom board includes a base on which a stator having a coil assembly is mounted. An axial hole is defined in the base of the bottom board, and a bearing is mounted in the axial hole for rotatably holding a shaft of s a rotor. A plurality of magnetic pole faces are formed on the base of the bottom board by means of punching the base of the bottom board. The magnetic pole faces surround the axial hole and are adjacent to the coil assembly of the stator.

Other objects, advantages and novel features of this invention will become more apparent from the following detailed description when taken in 0 conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is an exploded perspective view of a heat-dissipating fan with a first embodiment of a casing in accordance with the present invention; Fig. 2 is a top view of the heat-dissipating fan in Fig. 1; Fig 3 is a sectional view taken along line 3-3 in Fig. 2; Fig. 4 is an exploded perspective view similar to Fig. 1, with an upper cover being attached to the heat-dissipating fan in Fig. 1; Fig. 5 is a sectional view of the heat-dissipating fan in Fig. 4; Fig 6 is an exploded perspective of a modified embodiment of the go heat-dissipating fan in accordance with the present invention; Fig. 7 is a sectional view of the heat-dissipating fan in Fig. 6; and Fig. 8 is a perspective view, partly exploded, of a conventional heat dissipating fan.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is now to be described hereinafter in detail, in which the same reference numerals are used for the same parts as those in the

s prior art.

Referring to Figs. 1 through 3, a first embodiment of a casing for a heatdissipating fan in accordance with the present invention comprises a casing 10 that is an integral member formed by means of punching a single magnetically conductive plate 1. The casing 10 after formation includes a o bottom board 1 Oa having a base 12 on a central portion thereof and a plurality of sidewalls 101 extending upwardly from a periphery of the bottom board, 1 Oa with a plurality of air outlets 102 being defined in the bottom board 10a and surrounding the base 12. The base 12 is connected by a plurality of ribs 11 to the remaining portion of the bottom board 10a. The ribs 11 and the air outlets l 02 are simultaneously formed during punching of the magnetically conductive plate 1.

Parts for a stator such as a coil assembly 20 and a circuit board 40 are mounted on the base 12. An axle tube 14 is mounted to a central portion of the base 12. Alternatively, the axle tube 14 is formed by means of punching; 'lamely, the axle tube 14 is integral with the base 12. The coil assembly 20 and the circuit board 40 are mounted around the axle tube 14. Further, a plurality of magnetic pole faces 13 that are formed by means of punching the base 12 (see the holes 131 after punching), with the magnetic pole faces 13 being spaced by angular intervals around the an axial hole 141 defined in the axle tube 14. The magnetic pole faces 13 are adjacent to the coil assembly 20.

A bearing 142 is mounted in the axial hole 141 for rotatably holding a shaft 31 of a rotor 30. Also mounted in the axial hole 141 is a support member 143 on which a distal end of the shaft 31 of the rotor 30 rests, providing a stable rotation for the rotor 30. After the shaft 31 of the rotor 30 is extended through the bearing 142 and retained in place by a retainer 311, a permanent magnet 33 on the rotor 30 and the magnetic pole faces 13 of the base 12 have an lo appropriate radial gap therebetween. Thus, when the coil assembly 20 is energized under the control of the drive circuit (not labeled) on the circuit boar 40, alternating magnetic fields are created in the radial gap by the magnetic pole faces 13, thereby driving the rotor 30 and its blades 32 to turn.

As shown in Figs. 4 and 5, an upper cover 15 is provided on top of the casing 10 for protecting the rotor 30. The upper cover 15 may be formed by molding injection, casting, or punching. Preferably, the upper cover 15 includes tour sidewalls 151, an air inlet 152, a plurality of fixing holes 153, and a plurality of protrusions 154. The fixing holes 153 of the upper cover 15 are al igned with fixing holes 103 defined in the corner portions of the bottom board 9' I Oa of the casing 10, and fasteners 16 are extended through the fixing holes 153 and 103, thereby securing the upper cover 15 to the casing 10. The protrusions 154 project from an inner periphery delimiting the air inlet 152 for preventing inadvertent disengagement of the rotor 30 from the casing 10 without adversely affecting the air flow.

Referring to Figs. 1 and 5, the base 12 may further include a slot 121 that is also formed as a result of punching. A wire 41 of the circuit board 40 s extends in the slot 121 of the base 12. Thus, a sensor 42 on a distal end of the wire 41 can be mounted in an associated one of the holes 131. The sensor 42 is positioned adjacent to the permanent magnet 33 of the rotor 30 for detecting polarity of the permanent magnet 33. Further, a top of each magnetic pole face 13 may include a notch 132 of an appropriate shape. These notches 132 create lo non-uniform alternating magnetic fields while the power is turned on, thereby driving the rotor 30 and its blade 32. Thus, the heat- dissipating fan in accordance with the present invention is easy to start.

Figs. 6 and 7 illustrate a second embodiment of the invention, wherein the casing 10 and the upper cover 15 are designed for a blower type heat dissipating fan. More specifically, in this embodiment, the casing 10 is also an integral member formed by means of punching a single magnetically conductive plate I. Nevertheless, space is preserved for providing a path for the air blown into the casing 10 while the rotor 30 drives winds for heat-dissipating purposes. Further, an air outlet 104 is defined in at least one of the sidewalls 9() 101 of the casing 10. The upper cover 15 includes an air inlet 152 corresponding to the location ofthe rotor 30. An air outlet 155 is defined in one ol the sidewalls 151 of the upper cover 15 and aligned with the air outlet 104 of

G

the casing 10. Further, at least one guide plate 156 is formed on the corner portions of the sidewalls 151 of the upper cover 15 for guiding air and for preventing generation of turbulence. Further, holes 102' forming air inlets may be defined in the bottom board lea of the casing 10 according to need.

As described above, a single magnetically conductive plate 1 is directly punched to form a casing 10 with the sidewalls 101, the ribs 11, the bottom board I Oa with the base 12, the magnetic pole faces 13, and the axial hole 141, with the circuit board 40, the coil assembly 20, and the magnetic pole faces 13 being preferably arranged in a radial direction on the bottom board lOa. The 0 number of the parts of the casing and the stator of the heat- dissipating fan and the overall thickness in the axial direction of the heat-dissipating fan are decreased without sacrificing the functions. Thus, the heat-dissipating fan and the casing 10 in accordance with the present invention can be used in notebook type computers as well as other delicate electronic devices.

While the principles of this invention have been disclosed in connection with specific embodiments, it should be understood by those skilled in the art that these descriptions are not intended to limit the scope of the invention, and that any modification and variation without departing the spirit of the invention is intended to be covered by the scope of this invention defined only by the JO appended claims.

Claims

WHAT IS CLAIM_D IS: l. A casing for a heat-dissipating fan, the casing 10

comprising a bottom board lOa and a plurality of sidewalls 101 extending from the bottom board 1 Oa, the bottom board 1 Oa and the sidewalls 101 being integrally formed by means of punching a magnetically conductive plate 1, the bottom board 1 Oa including a base 12, with a stator having a coil assembly 20 being adapted to be mounted on the base 12 ofthe bottom board lea, with an axial hole 141 being defined in the base 12 of the bottom board lea, with a bearing 142 being adapted to be mounted in the axial hole 141 for rotatably holding a shaft 3 1 of a lo rotor 30, and with a plurality of magnetic pole faces 13 being formed on the base 12 of the bottom board lea by means of punching the base 12 of the bottom board lea, with the magnetic pole faces 13 surrounding the axial hole l 4 l and being adjacent to the coil assembly 20 of the stator.
2. The casing for a heat-dissipating fan as claimed in claim 1, wherein i5 the magnetic pole faces 13 being spaced at angular intervals around the axial hole 141.
3. T he casing for a heat-dissipating fan as claimed in claim 1, wherein a plurality of ribs I I and a plurality of air outlets 102 being formed around the base 12 of the bottom board lOa by punching.

?0
4. The casing for a heat-dissipating fan as claimed in claim 1, wherein talc axial hole 141 being defined by means of directly punching the base 12 of the bottom board I Oa to form an axial tube 14.
5. The casing for a heat-dissipating fan as claimed in claim 1, wherein a notch 132 being defined in each of the magnetic pole faces 13.
6. The casing for a heat-dissipating fan as claimed in claim 1, wherein the stator including a circuit board 40.
7. The casing for a heat-dissipating fan as claimed in claim 6, wherein the circuit board 40 including a wire 41 and a sensor 42 attached to the wire 41, with the tease 120fthebottomboard lOaincludinga slot 121 through which the wire41 extends.
8. The casing for a heat-dissipating fan as claimed in claim 7, wherein o the sensor 42 being located in one of a plurality of associated holes 131 that are Iormed during punching for forming the magnetic pole faces 13.
9. The casing for a heat-dissipating fan as claimed in claim 1, wherein a plurality of fixing holes 103 being deemed in corner portions of the casing 10.
10. The casing for a heat-dissipating fan as claimed in claim 1, wherein an upper cover 15 being securely mounted on top of the casing 10.
11. The casing for a heat-dissipating fan as claimed in claim 10, wherein the upper cover 15 including an air inlet 152, with a plurality of protrusions 154 projecting from an inner periphery delimiting the air inlet 152 for preventing the rotor 30 from disengaging from the casing 10.

(I
12. The casing for a heat-dissipating fan as claimed in claim 10, wherein the upper cover 15 including a plurality of first fixing holes 153, with a plurality of second fixing holes 103 being defined in corner portions of the bottom board lea of the casing 10 and aligned with the first fixing holes 153 of the upper cover 15, and with fasteners 16 extending through the first fixing holes 153 of the upper cover 15 and the second fixing holes 103 of the bottom board lea.
13. The casing for a heat-dissipating fan as claimed in claim 10, wherein the upper cover 15 including four sidewalls 151, with at least one of the sidewalls 151 of the upper cover 15 having an air outlet 155, with at least one of the sidewalls 101 of the casing 10 having an air outlet 104 aligned with the air outlet 155 of the upper cover 15.

lo
14. The casing for a heat-dissipating fan as claimed in claim 10, wherein the upper cover 15 further including a plurality of sidewalls 151 and a plurality of corner portions, with the upper cover 15 having a guide plate 156 on at least one of the corner portions thereof for guiding air.