Centrifugal fan comprising a sidewall and plurality of air deflectors forming a plurality of airflow entry tunnels to sequentially expand a flow channel outwardly in a radial direction

A centrifugal fan includes an impeller, a motor and a fan frame. The motor is connected with the impeller and configured to drive the impeller. The fan frame includes a base plate, a top plate, a sidewall and air deflectors. The impeller is disposed between the base plate and the top plate. The sidewall is disposed on the base plate between the base plate and the top plate. A flow channel is between the impeller and the sidewall. The air deflectors are directly connected to the base plate and the top plate, and disposed toward an air outlet and sequentially at different radial positions outwardly from the sidewall along a forward circumferential direction toward an air outlet with respect to the impeller to sequentially expand the flow channel outwardly in a radial direction at different circumferential positions along the forward circumferential direction with respect to the impeller. The airflow entry tunnels are formed by the air deflectors between the base plate and the top plate.

BACKGROUND OF THE INVENTION

Field of Invention

The disclosure is relative to a centrifugal fan, especially relative to a centrifugal fan for increasing the input air and with stable output air.

Related Art

In recent years, with advances in technology, the electronic devices (ex: notebook) are gradually developing with high-performance, high speed and high frequency. Accordingly the computing loading of the inside components of the electronic device increases and the temperature of the electronic device is getting higher. If a good heat dissipation solution is not utilized efficiently in the electronic device, the stability will be influenced and the life of the electronic device will be shortened. Thus, generally a fan (ex: centrifugal fan) will be installed inside of the electronic device for heat dissipation.

FIG. 1is a top view of a prior art centrifugal fan1. As shown inFIG. 1, the centrifugal fan1includes an air outlet O1and an air inlet (not shown). A sidewall11is disposed besides a flow channel P1of the centrifugal fan1. The input air is limited to the size and the position of the air inlet. The input air is difficult to increase. Additionally, the centrifugal fan1has a non-uniform problem that the output air is collected at the strong wind area H.

Recently the most electronic devices are developed to have a thinner size. The thinner size of the electronic devices will decrease the inner space of the electronic devices. Accordingly, it is an important subject to provide a centrifugal fan with an increasing input air and a stable/uniform output air in the same fan volume.

In US publication 2013/0071238, with reference toFIGS. 1A and 1B, an auxiliary flow102is guided by the guiding grooves127, and enters the housing120through the auxiliary inlets124. Each guiding groove127comprises an inclined guiding slope128and a guiding sheet125. The guiding groove127with its guiding sheet125are purposely only located at the upper plate120T, so the involute sidewall123does not need additionally expanding its width outwardly in radial direction. Thus, the guiding groove127and the guiding sheet125would not be modified to be directly connected to the lower plate120B because such modification results in that the auxiliary flow102through the auxiliary inlet124obstruct the major flow101.

In U.S. Pat. No. 2,050,523, the air inlets15are provided in the top of hood member8adjacent the forward portion thereof, but the extending louver boards16are not toward the discharge opening11.

SUMMARY OF THE INVENTION

In view of foregoing subject, an objective of the present disclosure is to provide a centrifugal fan with an increasing input air and a stable/uniform output air in the unchanged volume of the fan.

The disclosure discloses a centrifugal fan including an impeller, a motor and a fan frame. The motor is connected with the impeller and configured to drive the impeller. The fan frame includes a base plate, a top plate, a sidewall, a plurality of air deflectors and a plurality of airflow entry tunnels. The impeller is disposed between the base plate and the top plate. The sidewall is disposed on the base plate between the base plate and the top plate. A flow channel is between the impeller and the sidewall. The air deflectors are directly connected to the base plate and the top plate, and separately disposed toward an air outlet and sequentially at different radial positions outwardly from the sidewall along a forward circumferential direction toward an air outlet with respect to the impeller to sequentially expand the flow channel outwardly in a radial direction at different circumferential positions along the forward circumferential direction with respect to the impeller. The airflow entry tunnels are formed by the air deflectors between the base plate and the top plate.

In one embodiment, the two adjacent air deflectors are overlapped by a non-zero overlapping length along the forward circumferential direction so that the two adjacent air deflectors, the base plate and the top plate firm one of the airflow entry tunnels. One of the air deflectors and the sidewall are overlapped by a non-zero overlapping length along the forward circumferential direction so that the one of the air deflectors, the sidewall, the base plate and the top plate form one of the airflow entry tunnel.

In one embodiment, two ends of one the airflow entry tunnels have a same height with respect to the base plate. Two ends of one the air deflectors have a same height with respect to the base plate.

In one embodiment, two ends of one of the air deflectors have a same distance to the impeller.

In one embodiment, the one of the air deflectors is arc-shaped and its arc center is at the impeller.

In one embodiment, the air outlet and an opposite point are respectively at two opposite sides of the impeller, and a forward included angle between the opposite point and a forward end of the sidewall is between 15 degrees and 60 degrees.

In one embodiment, the forward included angle is 50 degrees.

In one embodiment, a pressurization area is from the air outlet through the opposite point to a forward end of the sidewall along the sidewall, and a combinational air input area is from the forward end of the sidewall to the air outlet along the air deflectors.

In one embodiment, a normal line of the air outlet is toward through a rotation center of the impeller, and the opposite point is at the normal line.

In one embodiment, an included angle from the air deflector which is closest to the sidewall to the normal line of the air outlet along the forward circumferential direction with respect to the impeller is between 120 degrees and 165 degrees.

In one embodiment, an included angle from an entry opening of the airflow entry tunnel which is closest to the air outlet to the normal line of the air outlet along the forward circumferential direction with respect to the impeller is below 90 degrees.

In one embodiment, the flow channel comprises circumferential sections from the impeller outwardly, the innermost section of the circumferential sections is defined within a reference circumferential position at which the sidewall is, other sections of the circumferential sections are respectively defined within the circumferential positions at which the air deflectors are, and the innermost section does not overlap the other sections in a direction from the base plate to the top plate.

In one embodiment, outside airflows flow into the other sections via the airflow entry tunnels.

In one embodiment, the sidewall comprises a throat part, and the air deflectors and the throat part are disposed at two opposite sides of the impeller, respectively.

In one embodiment, dusts in the centrifugal fan are exhausted from the centrifugal fan via the airflow entry tunnels when the impeller is driven to rotate reversely by the motor.

In one embodiment, the air deflectors are discrete sidewalls of the fan frame.

In one embodiment, the base plate and the top plate do not protrude from the air deflectors.

In one embodiment, an included angle between the air outlet and the air deflector which is closest to the sidewall along the forward circumferential direction with respect to the impeller is between 120 degrees and 165 degrees.

The disclosure discloses a centrifugal fan including an impeller, a motor and a fan frame. The motor is connected with the impeller and configured to drive the impeller. The fan frame includes a base plate, a top plate, a sidewall, a plurality of air deflectors and a plurality of airflow entry tunnels. The impeller is disposed between the base plate and the top plate. The sidewall is disposed on the base plate between the base plate and the top plate. A flow channel is between the impeller and the sidewall. The air deflectors are directly connected to the base plate and the top plate, and separately disposed toward an air outlet and sequentially at different radial positions outwardly from the sidewall along a forward circumferential direction toward an air outlet with respect to the impeller to sequentially expand the flow channel outwardly in a radial direction at different circumferential positions along the forward circumferential direction with respect to the impeller. The airflow entry tunnels are formed by the air deflectors between the base plate and the top plate. The air outlet and an opposite point are respectively at two opposite sides of the impeller. A forward included angle between the opposite point and a forward end of the sidewall is between 15 degrees and 60 degrees. An included angle from an entry opening of the airflow entry tunnel which is closest to the air outlet to the normal line of the air outlet along the forward circumferential direction with respect to the impeller is below 90 degrees.

The disclosure discloses a centrifugal fan including an impeller, a motor and a fan frame. The motor is connected with the impeller and configured to drive the impeller. The fan frame includes a base plate, a top plate, a sidewall, a plurality of air deflectors and a plurality of airflow entry tunnels. The impeller is disposed between the base plate and the top plate. The sidewall is disposed on the base plate between the base plate and the top plate. A flow channel is between the impeller and the sidewall. The air deflectors are directly connected to the base plate and the top plate, and separately disposed toward an air outlet and sequentially at different radial positions outwardly from the sidewall along a forward circumferential direction toward an air outlet with respect to the impeller to sequentially expand the flow channel outwardly in a radial direction at different circumferential positions along the forward circumferential direction with respect to the impeller. The airflow entry tunnels are formed by the air deflectors between the base plate and the top plate. The air outlet and an opposite point are respectively at two opposite sides of the impeller. A forward included angle between the opposite point and a forward end of the sidewall is between 15 degrees and 60 degrees. A pressurization area is from the air outlet through the opposite point to a forward end of the sidewall along the sidewall. A combinational air input area is from the forward end of the sidewall to the air outlet along the air deflectors. The air deflectors are discrete sidewalls of the fan frame, and the base plate and the top plate do not protrude from the air deflectors.

According to above, the centrifugal fan of the present disclosure can increase the input air by that air deflectors set separately and along the extension direction along the flow channel and towards to the air outlet and the outside airflow can flow in the fan via the space between the two adjacent air deflectors. Additionally, the airflow flowing into the fan can be flowing along the air deflectors to the air outlet for stable/uniform output air.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 2Ais an exploded view of a centrifugal fan according to a preferred embodiment of the present disclosure andFIG. 2Bis a top view of the centrifugal fan inFIG. 2A. For easily understanding,FIG. 2Bdoes not show the top plate314inFIG. 2A. Referring toFIGS. 2A and 2B, the centrifugal fan3of this embodiment includes a fan frame31, an impeller32and a motor33. The centrifugal fan3can be received in an electronic device as a heat dissipation system. The electronic device can be a notebook computer.

The fan frame includes a base plate311, a sidewall312and a plurality of air deflectors313. In the embodiment, the centrifugal fan includes three air deflectors. However, the number of the air deflector can depend on real requirements.

The sidewall312and the air deflectors313are disposed on the base plate311. An accommodating space S and an air outlet O2is disposed by the base plate311, the sidewall312and the air deflectors313.

The impeller32includes a wheel321and a plurality of fan blades322. The impeller is received in the accommodating space S and mounted on the motor33. The motor is connected with the impeller32and drives the impeller32to rotate. A flow channel P3(as shown inFIG. 2B) is disposed between the impeller32and the sidewall312. In the embodiment, the fan frame31further includes a top plate314. An air inlet O3is disposed in the top plate314. When the impeller is rotating, the outside air flows into the centrifugal fan3via the air inlet O3and the air in the centrifugal fan3flows along the flow channel P3to the air outlet O2. Then the air in the centrifugal fan3is exhausted via the air outlet O2.

In the embodiment, the air deflectors313are separately disposed along the extension direction of the flow channel and toward to the air outlet O2. In detail, the sidewall312in the embodiment includes a throat part3121and a guiding part3122. The throat part3121and the guiding part3122are respectively disposed at two ends of the sidewall312. The air deflectors313are separately disposed from the position. adjacent to the guiding part3122and toward to the air outlet O2. The air deflectors313and the throat part3121are disposed on the two sides of the impeller32. According to that the air deflectors are separately disposed, a gap D is formed between the two adjacent air deflectors313. In the embodiment, a distance of the gap D optimally is between 0.5 mm to 10 mm. In the embodiment, when the impeller is rotating, outside airflow can flow into the centrifugal fan3via the gap D, the air in the centrifugal fan3flows along the extension direction of the flow channel P3for increasing the input air.

In the embodiment, the outside air that flows into the centrifugal fan3can be guided to a low air pressure position by the air deflectors313. InFIG. 2B, the air deflectors313are arc-shaped. The outside airflow can be guided to a position near to the middle of the air outlet O2for the stable/uniform output air around the air outlet O2. It is noted that the shape of the air deflectors can be adjusted according to the real requirements, and it is not limited to shapes of the air deflectors as shown in the figures.

The following descriptions are relative to the relative positions of the air deflectors313.

In the embodiment, the air deflectors313at least include a first air deflector3131and a second air deflector3132. A distance between the second air deflector3132and the air outlet O2is smaller than a distance between the first air deflector3131and the air outlet O2. The second air deflector3132and the impeller32are disposed two opposite sides of the first air deflector3131.

In detail, the first air deflector3131includes a first end3131aand a second end3131b. The second end3131bis disposed adjacent to the second deflector3132. The second air deflector3132includes a third end3132aand a fourth end3132b. The third end3132is adjacent to the first air deflector3131. The third end3132aand the impeller32are disposed two opposite sides of the second end3131b. It means that the second air deflector3132is located at outside of the first air deflector3131.

In centrifugal fan3according to the embodiment of the present, the position of the air deflector313that is closer to the air outlet O2is disposed farther than the position of the air deflector313that is father from the air outlet O2. Therefore, the air deflectors313will not decrease the space of the whole flow channel and prevent to decrease the air inside the centrifugal fan.

Additionally, in the embodiment, the two adjacent air deflectors313are partially overlapped along a predetermined direction. InFIG. 2B, the first air deflector3131and the second air deflector3132are partially overlapped in the predetermined direction d3. In detail, the second end3131hof the first air deflector3131and the third end of the second air deflector3132are overlapped in the predetermined direction d3. The impeller32includes a rotation center C. The predetermined direction d3is a direction from the rotation center C to the second end3131b. Thus, when the impeller32rotates forwardly, the air in the centrifugal fan3exhausted via the gap D between the air deflector3131and the second air deflector3132can be prevented.

In the embodiment, the gap D is also disposed between the first end3131aof the first air deflector3131and the guiding part3122. The gap D is utilized for increasing the input air. The distance between the first air deflector3131and the impeller32is larger than the distance between the sidewall312and the impeller32. Accordingly the space of the flow channel will not be decreased by the first air deflector3131.

The distance between the sidewall312and the impeller32, the distance between the first air deflector3131and the impeller32, and the distance between second air deflector3132and the impeller32are increasing in turn. A width of the flow channel is larger increasingly. There is enough space that the outside airflow can flow via the gap D for increasing the air in the centrifugal fan3.

Additionally, in the embodiment, when the motor drives the impeller32to rotate reversely, a reverse airflow is generated in the centrifugal fan3. Dusts in the centrifugal fan3can be exhausted from the centrifugal fan3via the gap D between the two adjacent air deflectors to achieve the dust-removing function. A shape of the air deflectors313is arc-shaped to match the flow direction of the flow field. The dusts in the centrifugal fan3can be flowed along the arc-shaped air deflector and exhausted via the gap D.

FIGS. 2D-2Fare perspective diagrams showing the centrifugal fan3inFIGS. 2A-2C.FIG. 2Gis a schematic diagram showing the centrifugal fan3inFIGS. 2A-2C. InFIGS. 2A-2G, the impeller32is disposed between the base plate311and the top plate314. The sidewall312is between the base plate311and the top plate314. The air deflectors313are directly connected to the base plate311and the top plate314, and separately disposed toward the air outlet O2and sequentially at different radial positions R1˜R3outwardly from the sidewall312along a forward circumferential direction d1toward the air outlet with respect to the impeller32to sequentially expand the flow channel P3outwardly in a radial direction RD at different circumferential positions R1˜R3along the forward circumferential direction d1with respect to the impeller32. The airflow entry tunnels G1˜G3are formed by the air deflectors313between the base plate311and the top plate314.

The two adjacent air deflectors3131,3132are overlapped by a non-zero overlapping length along the forward circumferential direction d1so that the two adjacent air deflectors3131,3132, the base plate311and the top plate314form one airflow entry tunnel G2. The airflow entry tunnel G2is at the gap D and extended from the third end3132aof the air deflector3132to the second end3131bof the air deflector3131along the forward circumferential direction d1. The distance from the third end3132aof the air deflector3132to the second end3131bof the air deflector3131along the forward circumferential direction d1is greater than 0. The airflow entry tunnel G3is similar or same with the airflow entry tunnel G2. Further, one of the air deflectors311(air deflector3131) and the sidewall312are overlapped by a non-zero overlapping length along the forward circumferential direction d1so that the air deflectors3131, the sidewall312, the base plate311and the top plate314form the airflow entry tunnel G1. The airflow entry tunnel G1is at the gap D and extended from the first end3131aof the air deflector3131to a forward end3121of the sidewall312along the forward circumferential direction d1. The distance from the first end3131aof the air deflector3131to the forward end3121of the sidewall312along the forward circumferential direction d1is greater than 0.

A height of the air deflectors313is equal to a height of the airflow entry tunnels G1˜G3with respect to the base plate311. Regarding one air deflector313, for example the air deflector3131, its two ends3131a,3131bhave a same height with respect to the base plate311. For example, the air deflector3131has an equal height from one end3131ato the other end3131b. The air deflectors3132,3133are similar or same with the air deflector3131. Two ends of the airflow entry tunnel G2have a same height with respect to the base plate311. The airflow entry tunnel G2has an equal height from the third end3132ato the second end3131b. The airflow entry tunnels G1and G3are similar or same with the airflow entry tunnel G2. Further, the width of the airflow entry tunnels G1and G3is between 0.5 mm and 10 mm. The width of the airflow entry tunnels G1and G3can remain equal along the forward circumferential direction d1.

In addition, the two ends3131a,3131bof the air deflector3131have a same distance to the impeller32. For example, the air deflector3131ais arc-shaped and its arc center is at the impeller32. The arc center and the rotation center C may be at the same position. The air deflector3132is similar or same with the air deflector3131. The two ends of the air deflector3133have different distances to the impeller32, but in other embodiment the two ends of the air deflector3133can have a same distance to the impeller32.

InFIG. 2G, the air outlet O2and an opposite point Q are respectively at two opposite sides of the impeller32, and a forward included angle θ1between the opposite point Q and the forward end3121(or the air deflector closest to the sidewall312) is between 15 degrees and 60 degrees. The forward end3121(or the air deflector closest to the sidewall312) is ahead of the opposite point Q by the forward included angle θ1along the forward circumferential direction d1. For example, the forward included angle θ1is 50 degrees. A pressurization area PA is from the air outlet O2through the opposite point Q to the forward end3121along the sidewall312(along the forward circumferential direction d1), and a combinational air input area is from the forward end3121to the air outlet O2along the air deflectors313(along the forward circumferential direction d1). A normal line NL of the air outlet O2is toward through the rotation center C of the impeller32, and the opposite point Q is at the normal line NL.

Ahead of the forward end3121, an included angle θ2from the air deflector3131, which is closest to the sidewall312, to the air outlet O2or the normal line NL along the forward circumferential direction d1with respect to the impeller32is between 120 degrees and 165 degrees. The forward included angle θ1and the included angle θ2are supplementary angles. An included angle θ3from an entry opening of the airflow entry tunnel G3, which is closest to the air outlet O2, to the normal line NL along the forward circumferential direction d1with respect to the impeller32is below 90 degrees.

The flow channel P3comprises circumferential sections P30˜P33from the impeller32outwardly. The innermost section P30of the circumferential sections is defined within a reference circumferential position R0at which the sidewall312is. Other sections P31˜P33of the circumferential sections are respectively defined within the circumferential positions R1˜R3at which the air deflectors3131˜3133are. An extension arc line E0by a radius (from the rotation center C to the reference circumferential position R0) is extended from the forward end3121along the forward circumferential direction d1. Extension arc lines E1, E2by radii (from the rotation center C respectively to the reference circumferential positions R1, R2) are extended from the air deflectors3131,3132along the forward circumferential direction d1to a reference line RL. The extension arc lines E0˜E2do not intersect. The innermost section P30is within the extension arc line E0and does not overlap the other sections P31˜P33in a direction Z from the base plate311to the top plate314. The section P31is between the extension arc lines E0, E1and the air deflector3131. The sections P32˜P33are similar to the section P31. The other sections P31˜P33also do not overlap each other in the direction Z. Viewing along the direction Z from top, the sections P31˜P33are covered by the top plate314. The air inlet O3of the top plate314is connected to the innermost section P30. The innermost section P30is partially covered by the top plate314. The sections P31˜P33and part of the innermost section P30are at the combinational air input area.

In addition, the air deflector3133can have an arc section3133aand a straight section3133b. Along the forward circumferential direction d1, the arc section3133ais following the reference line RL, and the straight section3133bis ahead of the reference line RL. The arc center of the arc section3133ais at the impeller32. The air deflectors3131,3132and the arc section3133ahave the same arc center at the rotation center C.

The full heights of sections P30˜P33are from the base plate311to the top plate314and remain unchanged from the forward end3121to the air outlet O2. The full heights of the airflow entry tunnels G1˜G3are from the base plate311to the top plate314and remain unchanged along the forward circumferential direction d1. The heights of the sections P30˜P33and the airflow entry tunnels G1˜G3are equal.

Outside airflows flow into the other sections P31˜P33via the airflow entry tunnels G1˜G3. The outside airflows through the airflow entry tunnels G1˜G3would not interfere with air pressurization at the pressurization area PA. Further, dusts in the centrifugal fan3can be exhausted from the centrifugal fan3via the airflow entry tunnels G1˜G3when the impeller is driven to rotate reversely (the forward circumferential direction d1in reverse) by the motor.

Referring toFIG. 3,FIG. 3is a schematic diagram of different types of air deflector of the present disclosure. Different from the air deflectors313inFIGS. 2A-2G, a shape of air deflectors313ainFIG. 3is similar to a rectangle in a top view. Other characters of the centrifugal fan3inFIG. 3are similar to that of the centrifugal fan3inFIGS. 2A-2G. Please referring the preceding paragraphs and they are not repeated again.

FIGS. 4A-4Bare schematic diagrams showing a centrifugal fan3a.FIG. 4Ashows the appearance of the centrifugal fan3awhen viewing from top.FIG. 4Bshows the interior of the centrifugal fan3ainFIG. 4A.FIGS. 4C-4Fare perspective diagrams showing the centrifugal fan3ainFIGS. 4A-4B.FIG. 4Cshows the appearance of the centrifugal fan3a, andFIG. 4Dshows the interior of the centrifugal fan3ainFIG. 4C.FIG. 4Eshows the appearance of the centrifugal fan3a, andFIG. 4Fshows the interior of the centrifugal fan3ainFIG. 4E. InFIGS. 4A-4F, the air deflectors313are discrete sidewalls of the fan frame31. The base plate311and the top plate314do not protrude from the air deflectors313. The centrifugal fan3ainFIGS. 4A-4Fcan be obtained by modifying the centrifugal fan3inFIGS. 2A-2G. The modification includes removing the portion3111of the base plate311inFIGS. 2A-2Gand modifying the sidewall312inFIGS. 2A-2Ginto plate shape.

In summary, in the centrifugal fan, the air deflectors are disposed separately along the extension direction and toward to the air outlet. The outside airflow can flow in the centrifugal fan via the gap between the two adjacent air deflectors. Thus, the input air is increased. Additionally, the inside airflow can flow along the air deflectors to the air outlet for unifying the output air.

Comparing to the prior art, the flow channel of the centrifugal fan is not reduced according to the air deflectors. The centrifugal fan can overcome the problem that the air pressure in the fan is not uniform and noisy. Additionally, the dust in the fan can be exhausted easily, and is not accumulated in the gap.