200928109 •九、發明說明： 【發明所屬之技術領域】 本發明涉及一種離心風扇，特別係涉及一種適用於筆記 型電腦散熱之離心風扇。 【先前技術】 > 近年來隨著電子產業之發展，電子元件之性能不斷提 升，運算速度越來越快，其工作時所散發之熱量相應增加， 如果這些熱量不及時散發出去，將極大影響電子元件之性 能，使電子元件之運算速度降低，隨著熱量之不斷累積，還 可能燒毁電子元件，因此必須對電子元件進行散熱，比如在 筆記型電腦中，在有限之系統空間内，對電子元件散熱通常 採用佔用空間較小之離心風扇。 % 該離心風扇通常包括一扇框、一輪毅及以輪穀為中心呈BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centrifugal fan, and more particularly to a centrifugal fan suitable for heat dissipation of a notebook computer. [Prior Art] > In recent years, with the development of the electronics industry, the performance of electronic components has been continuously improved, the computing speed has become faster and faster, and the amount of heat emitted during the work has increased accordingly. If these heats are not released in time, it will greatly affect The performance of electronic components reduces the computational speed of electronic components. As heat builds up, it can burn electrical components. Therefore, electronic components must be dissipated. For example, in a notebook computer, in a limited system space, The cooling of electronic components usually uses a centrifugal fan that takes up less space. % The centrifugal fan usually consists of a frame, a wheel and a center of the valley.
|J 輻射狀向外延伸之複數扇葉，該扇框具有分別位於其頂面和 底面之上、下進風口及側面之一出風口。工作時，通過扇葉 旋轉帶動周圍空氣流動，將從進風口進入之軸向氣流轉向為 沿該輪轂之徑向氣流後從出風口排出。組裝時，該扇葉與扇 框之頂面與底面之間通常需保證至少1mm左右之間隙，以 防止扇葉轉動時與扇框產生摩擦。而由於風扇運轉時其内部 與進風口之間存在較大之氣壓差，容易使得該内部之高壓氣 流依循該間隙回流到低壓之進風口處而產生噪音，不利用風 200928109 量之充分利用。並且，氣流從進風口進入風扇内部之過程 '中，被風扇内部已經加壓之氣流阻擋，使得進入氣流與回流 .氣流相互干擾，影響風扇性能。 【發明内容】 有鑒於此，有必要提供一種具有較小噪音、同時防止進入 氣流與風扇内高壓氣流之間產生相互干擾之離心風扇。 一種離心風扇，包括扇框及收容於扇框内之定子和轉 ®子，該扇框包括頂板、底板及連接頂板與底板之側板，該頂 板和底板上至少其中之一形成有一入風口，該入風口之周緣 向扇框之内部環設有一擋風壁。 與習知技術相比，通過於入風口之周緣設置一擋風壁， 該擋風壁可阻隔該風扇内之高壓氣流回流並從入風口洩漏 出去，從而減少從入風口進入氣流與風扇内高壓氣流之間相 互干擾，使得入風口進氣更容易吸入，同時提高該離心風扇 _之進風之利用效率，達到降低噪音及增加風量和風壓之目 的。 【實施方式】 如圖1及圖2所示，該離心風扇包括一扇框20、收容於 該扇框20内之一定子（圖未示）及相對於該定子旋轉之一 轉子40。 該扇框20包括一頂板21、一底板22及連接於該頂板 21及底板22之間並與底板22 —體成型之側板23。該頂板 7 200928109 21、底板22與側板23共同形成一容置所述定子和轉子40 _之容置空間。該扇框20之頂板21與底板22平行設置，分 ‘設於該轉子40之上下兩側。該頂板21與底板22之中央位 置，即正對轉子40之位置處分別形成圓形之上、下入風口 24a、24b，該側板23於扇框20之一侧.形成一出風口 25，其 中，該上入風口 24a之直徑大於下入風口 24b之直徑。一擋 風壁26沿下入風口 24b之周緣向上延伸一定高度形成，該 擋風壁26凸伸出底板22之頂面220,並環繞在下入風口 24b ®之周圍以形成一直徑大小基本上等於該下入風口 24b之直徑 大小之圓環柱形之進風通道。該擋風壁26之高度大致為 1.5mm ( millimeter )，相當於將下入風口 24b之位置上移 1.5mm至離心風扇内部，從而引導該下入風口 24b處之進風 以垂直進入為主要方式。 請一併參閱圖3，該轉子40包括一輪轂41、環設於該 輪轂41外圍之複數扇葉42及設於所述扇葉42遠離輪轂41 ❹之末端之頂面並與其相互連接之一葉盤44。每一扇葉42包 括與輪轂41相連接之第一扇葉部422及高度大於該第一扇 葉部422之第二扇葉部424，其中，該第二扇葉部424與對 應之第一扇葉部422之末端為平滑連接，以減少該連接部位 對氣流之阻力，且該扇葉42之第一扇葉部422之下端與第 二扇葉部424之下端之相接部位正對擋風壁26之上方，並 與擋風壁26之頂面相隔大致0.5mm之距離，以避免風扇工 作時扇葉42與擋風壁26之間產生磨擦。該第二扇葉部424 收容在該擋風壁26與扇框20之側板23之間，且該第二扇 8 200928109 葉部424於靠近擋風壁26之一侧與擋風壁26之間形成大致 •為0.5mm寬度之間隙，因而其高度不受擋風壁26高度之限 .制，該第二扇葉部424之底端與扇框20之底板22之間間隔 1mm左右之間隙。 該葉盤44與扇葉42通過注塑方法一體成型。該葉盤44 包括一環形之頂壁441、從頂壁441外周緣垂直向下延伸之 呈環形之側壁442及從侧壁442之底端水準向外延伸之折邊 443。頂壁441收容於扇框20之上入風口 24a内，其上表面 ❿與頂板21之上表面相平齊，其外徑之大小大致與扇葉42之 外徑相同且略小於上入風口 24a之大小，且其内徑之大小與 下入風口 24b之大小大致相同。該葉盤44之頂壁441覆蓋 於扇葉42之上表面上，側壁442與第二扇葉部424之最外 側邊緣424a對齊並包覆於所述第二扇葉部424之最外側邊 緣424a之頂端之外圍，而折邊443則延伸至扇框20之頂板 21之内侧邊緣之正下方，因此葉盤44取代一部分扇框20 ^覆蓋該上入風口 24a大於下入風口 24b之部分，可使原來直 徑較大之上入風口 24a之實際入風面積減小至基本上與下入 風口 24b相等。為避免該離心風扇工作時轉子40高速轉動 與頂板21之間產生摩擦，該葉盤44之側壁442(即頂壁441 之外周緣）與頂板21之上入風口 24a處之内周緣之間及折 邊443與頂板21之間分別間隔一微小之間距。 該葉盤44設置於扇框20之上入風口 24a内，頂壁441 之位置與該扇框20之頂板21之位置相齊平，扇葉42之第 二扇葉部424之頂端直接延伸至與該葉盤44之頂壁441連 9 200928109 接成一體，故，扇葉42與扇框20之頂板21之間沿軸向無 •需預留間隙，從而可適當增加扇葉42之掃風截面高度。工 • 作時，轉子40高速轉動將上、下入風口 24a、24b進入之轴 向氣流轉向為沿輪轂41之徑向氣流，從而在扇葉42末端與 扇框20之側板23之間形成一高壓氣流通道。由於扇框20 之底板22上之擋風壁26之阻擋，風扇内之高壓氣流不易經 由該扇葉42之底端與扇框20之底板22之間形成之間隙回 流至下入風口 24b處而從該下入風口 24b洩漏出去。並且該 ❿葉盤44之側壁442可視為設於上入風口 24a處之擋風壁， 由於該葉盤44之侧壁442之阻擋，風扇内之高壓氣流不易 經由該葉盤44之折邊443與扇框20之頂板21之間形成之 間隙回流至上入風口處24a而從該上入風口 24a洩漏出去。 通過扇框20之底板22上擋風壁26及葉盤44之側壁442防 止風扇内之高壓氣流從其上、下入風口 24a、24b洩漏出去， 可提高該離心風扇之進風之利用效率，並減少紊流，使得 ❹上、下入風口 24a、24b進氣更容易吸入，從而達到降低噪 音及增加風量和風壓之目的。另外，該扇框20之底板22上 之擋風壁26將下入風口 24b之位置上移至該風扇内部，從 而引導下入風口 24b處之進風垂直進入後即被扇葉42掃入 高壓氣流通道内，使得進風順暢，減少在中途被高壓氣流之 阻擋，進一步有利於達到降低噪音及增加風量和風壓之目 的。具體實施時，擋風壁26之高度變化以於1.5mm至2.2mm 之間變化為佳，當然也可以根據具體情況進行調整。 圖4所示為本發明離心風扇之第二實施例，其與上述第 10 200928109 實施例之差別在於扇框20a之頂板2la上之上入風口 240a -之直徑與底板22a上之下入風口 240b之直徑相等，且葉盤 • 44a之結構與第一實施例中之葉盤44不同。具體而言，該葉 盤44a包括一環形之圓盤440a及從該圓盤440a之内周緣垂 直向上延伸之一環形之側壁442a。該圓盤440a與扇葉42a 上方之末端連接並位於扇框20a之頂板21a之下方，而侧壁 442a則向上延伸至與該扇框20a之頂板21a大致相平。工作 時，該側壁442a可视為設於該上入風口 24〇a處之擔風壁， 該側壁442a阻擔風扇内之高壓氣流經由葉盤4如之頂壁 440a之上方之間形成之間隙回流至上入風口 24〇a處而從該 上入風口 240a洩漏出去，並能引導從上入風口 24〇&處之進 風以垂直進入為主要方式，達到降低噪音及增加風量和風壓 之目的。 圖5所示為本發明離心風扇之第三實施例，其與上述第 二實施例之區別在於扇框20b之頂板21b之上入風口 242a ❹之周緣向下延伸形成一擋風壁26b，而扇葉42b之頂端不設 置葉盤44a。該擒風壁鳩之設置方式與及其作用方式均同 如所述，在此不資述。 综上所述，本發明符合發明專利之要件，爰依法提出專利 申請。惟以上料者僅為本發明之較佳實施例，舉凡熟悉本案 技藝之人士，在爰依本發明精神所作之等效修飾或變化，皆應 涵蓋於以下之申請專利範圍内。 【圖式簡單說明】 11 200928109 圖1為本發明離心風扇一較佳實施例之組裝圖。 圖2為圖1中離心風扇之分解圖。 - 圖3為圖1中離心風扇沿III-III線之剖面示意圖。 圖4為本發明離心風扇之第二實施例之剖面示意圖。 圖5為本發明離心風扇之第三實施例之剖面示意圖。 【主要元件符號說明】 扇框 20、20a、20b 頂板 21、21a 底板 22 頂面 220 侧板 23 上入風口 24a、240a、242a 下入風口 24b 、 240b 出風口 25 擋風壁 26、26b 轉子 40 輪轂 41 扇葉 42、42a 第一扇葉 422 第二扇葉 424 邊緣 424a 葉盤 44 > 44a 頂壁 折邊 441 > 441a 443 側壁 442、442a ❿ 12|J Radially extending a plurality of blades having air outlets on the top and bottom surfaces, the lower air inlet and the side, respectively. During operation, the fan air rotates to drive the surrounding air to flow, and the axial airflow entering from the air inlet is turned into a radial airflow along the hub and then discharged from the air outlet. When assembling, it is usually necessary to ensure a clearance of at least about 1 mm between the fan blade and the top surface and the bottom surface of the fan frame to prevent friction between the fan blade and the fan frame. However, since the fan has a large air pressure difference between the inside and the air inlet, it is easy to cause the internal high-pressure air to flow back to the low-pressure air inlet to generate noise, and the wind is not fully utilized. Moreover, the airflow from the air inlet to the inside of the fan is blocked by the airflow that has been pressurized inside the fan, so that the incoming airflow and the recirculation flow interfere with each other, affecting the performance of the fan. SUMMARY OF THE INVENTION In view of the above, it is necessary to provide a centrifugal fan that has less noise while preventing mutual interference between the incoming airflow and the high-pressure airflow in the fan. A centrifugal fan includes a fan frame and a stator and a rotary tool housed in the fan frame, the fan frame includes a top plate, a bottom plate, and a side plate connecting the top plate and the bottom plate, and at least one of the top plate and the bottom plate forms an air inlet. The outer edge of the air inlet is provided with a windshield wall to the inner ring of the fan frame. Compared with the prior art, a windshield wall is disposed on the periphery of the air inlet, the windshield wall can block the high-pressure airflow in the fan from flowing back and leaking out from the air inlet, thereby reducing the airflow from the air inlet and the high pressure in the fan. The mutual interference between the airflows makes the air intake of the air inlet easier to inhale, and at the same time, the utilization efficiency of the air inlet of the centrifugal fan is improved, and the purpose of reducing noise and increasing air volume and wind pressure is achieved. [Embodiment] As shown in Figs. 1 and 2, the centrifugal fan includes a frame 20, a stator (not shown) housed in the frame 20, and a rotor 40 that rotates relative to the stator. The frame 20 includes a top plate 21, a bottom plate 22, and a side plate 23 connected between the top plate 21 and the bottom plate 22 and integrally formed with the bottom plate 22. The top plate 7 200928109 21, the bottom plate 22 and the side plate 23 together form a receiving space for accommodating the stator and the rotor 40. The top plate 21 of the frame 20 is disposed in parallel with the bottom plate 22, and is disposed on the upper and lower sides of the rotor 40. The central position of the top plate 21 and the bottom plate 22, that is, the position facing the rotor 40, respectively form a circular upper and lower air inlets 24a, 24b. The side plate 23 is formed on one side of the fan frame 20 to form an air outlet 25, wherein The diameter of the upper air inlet 24a is larger than the diameter of the lower air inlet 24b. A windshield wall 26 is formed extending upwardly along a circumference of the lower air inlet 24b. The windshield wall 26 protrudes from the top surface 220 of the bottom plate 22 and surrounds the lower air inlet 24b® to form a diameter substantially equal to The circular inlet-shaped air inlet passage of the diameter of the lower air inlet 24b. The height of the windshield wall 26 is approximately 1.5 mm (millitemeter), which is equivalent to moving the position of the lower air inlet 24b upward by 1.5 mm to the inside of the centrifugal fan, thereby guiding the inlet air at the lower air inlet 24b to enter vertically as the main mode. . Referring to FIG. 3 together, the rotor 40 includes a hub 41, a plurality of blades 42 disposed around the periphery of the hub 41, and a top surface of the blade 42 away from the end of the hub 41 and connected to each other. Disk 44. Each of the blades 42 includes a first blade portion 422 coupled to the hub 41 and a second blade portion 424 having a height greater than the first blade portion 422, wherein the second blade portion 424 and the corresponding first portion The end of the blade portion 422 is a smooth connection to reduce the resistance of the connecting portion to the airflow, and the lower end of the first blade portion 422 of the blade 42 and the lower end of the second blade portion 424 are opposite each other. Above the wind wall 26, and spaced apart from the top surface of the windshield wall 26 by a distance of approximately 0.5 mm to avoid friction between the fan blade 42 and the windshield wall 26 during operation of the fan. The second blade portion 424 is received between the windshield wall 26 and the side plate 23 of the fan frame 20, and the second fan 8 200928109 leaf portion 424 is adjacent to one side of the windshield wall 26 and the windshield wall 26 A gap of approximately 0.5 mm width is formed, and thus the height is not limited by the height of the windshield wall 26. The bottom end of the second blade portion 424 is spaced apart from the bottom plate 22 of the frame 20 by a gap of about 1 mm. The leaf disc 44 and the blade 42 are integrally formed by an injection molding method. The leaf disc 44 includes an annular top wall 441, an annular side wall 442 extending vertically downward from the outer periphery of the top wall 441, and a hem 443 extending outwardly from the bottom end of the side wall 442. The top wall 441 is received in the air inlet 24a of the fan frame 20, and the upper surface ❿ is flush with the upper surface of the top plate 21, and the outer diameter is substantially the same as the outer diameter of the blade 42 and slightly smaller than the upper air inlet 24a. The size of the inner diameter is substantially the same as the size of the lower air inlet 24b. The top wall 441 of the leaf disc 44 covers the upper surface of the blade 42 and the side wall 442 is aligned with the outermost edge 424a of the second blade portion 424 and covers the outermost edge 424a of the second blade portion 424. The periphery of the top end, and the flange 443 extends directly below the inner edge of the top plate 21 of the fan frame 20, so that the leaf disk 44 replaces a portion of the fan frame 20 to cover the portion of the upper air inlet 24a larger than the lower air inlet 24b. The actual air inlet area of the air inlet 24a having a larger diameter is reduced to be substantially equal to the lower air inlet 24b. In order to avoid friction between the high speed rotation of the rotor 40 and the top plate 21 when the centrifugal fan is in operation, the side wall 442 of the leaf disc 44 (ie, the outer periphery of the top wall 441) and the inner periphery of the air inlet 24a above the top plate 21 and The flange 443 and the top plate 21 are spaced apart by a slight distance. The leaf disc 44 is disposed in the air inlet 24a above the fan frame 20. The position of the top wall 441 is flush with the position of the top plate 21 of the fan frame 20. The top end of the second blade portion 424 of the fan blade 42 extends directly to It is integrated with the top wall 441 of the leaf disc 44, 9 200928109. Therefore, there is no need to reserve a gap between the blade 42 and the top plate 21 of the fan frame 20, so that the wind of the fan blade 42 can be appropriately increased. Section height. During operation, the rotor 40 rotates at a high speed to steer the axial airflow entering the upper and lower air inlets 24a, 24b into a radial airflow along the hub 41, thereby forming a gap between the end of the blade 42 and the side panel 23 of the fan frame 20. High pressure air flow channel. Due to the blockage of the windshield wall 26 on the bottom plate 22 of the fan frame 20, the high-pressure airflow in the fan is not easily returned to the lower air inlet 24b via the gap formed between the bottom end of the blade 42 and the bottom plate 22 of the fan frame 20. Leaked from the lower air inlet 24b. The side wall 442 of the blade 44 can be regarded as a windshield disposed at the upper air inlet 24a. Due to the blocking of the side wall 442 of the blade 44, the high pressure airflow in the fan is not easily passed through the flange 443 of the blade 44. A gap formed between the top plate 21 of the frame 20 is returned to the upper air inlet 24a and leaked from the upper air inlet 24a. The windshield wall 26 of the bottom plate 22 of the fan frame 20 and the side wall 442 of the leaf disc 44 prevent the high-pressure airflow in the fan from leaking out from the upper and lower air inlets 24a, 24b, thereby improving the utilization efficiency of the centrifugal fan. The turbulence is reduced, so that the intake air of the upper and lower air inlets 24a, 24b is more easily inhaled, thereby achieving the purpose of reducing noise and increasing air volume and wind pressure. In addition, the windshield wall 26 on the bottom plate 22 of the fan frame 20 moves the position of the lower air inlet 24b to the inside of the fan, so that the air entering the lower air inlet 24b is vertically scanned, and then the blade 42 is swept into the high voltage. In the airflow passage, the air inlet is smooth, and the middle air is blocked by the high-pressure airflow, which further helps to reduce noise and increase air volume and wind pressure. In the specific implementation, the height change of the windshield wall 26 is preferably changed between 1.5 mm and 2.2 mm, and of course, it can be adjusted according to specific conditions. 4 is a second embodiment of the centrifugal fan of the present invention, which differs from the above-mentioned 10th 200928109 embodiment in the diameter of the air inlet 240a on the top plate 21a of the fan frame 20a and the air inlet 240b on the bottom plate 22a. The diameters are equal, and the structure of the leaf disc 44a is different from the leaf disc 44 in the first embodiment. Specifically, the disk 44a includes an annular disk 440a and an annular side wall 442a extending vertically upward from the inner periphery of the disk 440a. The disc 440a is coupled to the upper end of the blade 42a and located below the top plate 21a of the fan frame 20a, and the side wall 442a extends upwardly to be substantially flush with the top plate 21a of the frame 20a. In operation, the side wall 442a can be regarded as a wind wall provided at the upper air inlet 24a, and the side wall 442a blocks the gap between the high pressure airflow in the fan and the upper surface of the leaf wall 4 such as the top wall 440a. Returning to the upper air inlet 24〇a and leaking out from the upper air inlet 240a, and guiding the air inlet from the upper air inlet 24〇& to enter vertically as the main way to reduce noise and increase air volume and wind pressure . Figure 5 is a third embodiment of the centrifugal fan of the present invention, which differs from the second embodiment in that the peripheral edge of the air inlet 242a of the top plate 21b of the fan frame 20b extends downward to form a windshield wall 26b. The tip end of the blade 42b is not provided with the leaf disc 44a. The arrangement of the hurricane tick and its mode of action are the same as described above, and are not mentioned here. In summary, the present invention complies with the requirements of the invention patent and submits a patent application according to law. The above are only the preferred embodiments of the present invention, and equivalent modifications or variations made by those skilled in the art will be included in the following claims. BRIEF DESCRIPTION OF THE DRAWINGS 11 200928109 FIG. 1 is an assembled view of a preferred embodiment of a centrifugal fan of the present invention. Figure 2 is an exploded view of the centrifugal fan of Figure 1. - Figure 3 is a schematic cross-sectional view of the centrifugal fan of Figure 1 taken along line III-III. Figure 4 is a cross-sectional view showing a second embodiment of the centrifugal fan of the present invention. Figure 5 is a cross-sectional view showing a third embodiment of the centrifugal fan of the present invention. [Main component symbol description] Fan frame 20, 20a, 20b Top plate 21, 21a Base plate 22 Top surface 220 Side plate 23 Upper air inlet 24a, 240a, 242a Lower air inlet 24b, 240b Air outlet 25 Windshield 26, 26b Rotor 40 Hub 41 Blades 42, 42a First blade 422 Second blade 424 Edge 424a Leaf disc 44 > 44a Top wall flange 441 > 441a 443 Side wall 442, 442a ❿ 12