200920948 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，尤係涉及一種具有較 低噪音之離心風扇。 •【先前技術】 當則，隨著電腦產業迅速發展，筆記本電腦内之 晶片等發熱電子元件產生之熱量愈來愈多。為將該等 多餘熱量有效散發，通常在發熱電子元件之表面貼設 一散熱器，然後在該散熱器上設置—離心風扇，利用 該離心風扇產生之冷卻氣流對該散熱器進行強制散 熱，從而將發熱電子元件產生之熱量散去。由於風扇 所產生氣流之大小取決於風扇轉速，為使風扇之性能 得到進一步提高，須增大風扇旋囀速率。惟，風扇轉 速提高將會導致風扇所產生之噪音大幅度增加，而使 位於該離心風扇附近之使用者感到不適，甚至於無法 忍受。 如圖3所示，一離心風扇包括一扇框丄〇及收容於 該扇框10中之葉輪2〇 ’該扇框1 〇於頂面與底面分別 設置第一入風口 12與第二入風口 14，於側壁臨近出 風口處向内突出形成一舌部16，葉輪20於輪轂22外 周設置複數扇葉26,該葉輪20上還連接有一圓盤24, 該圓盤24貼設在扇葉26之末端並位於扇葉26之上 側，由於扇葉26與舌部16距離最近，當風從第一入 風口 12與第二入風口 14進入時在舌部16會產生多餘 7 200920948 風里’ 5亥等多餘風量在舌部16處受擠壓擾動而引起嚷 音。 【發明内容】 有馨於此’有必要提供一種具有較低噪音之離心 風扇。 >種離心風扇，包括—扇框和—收容於該扇框内 之葉輪。該扇框上設有—第一入風口、一出風口和一 與該出風口臨近之舌部。其中，該扇框上設有一位於 該第—入風口内之突起，該突起臨近該舌部。 ^ -種離d扇，包括_扇框和—收容於該扇框内 之葉輪》亥扇框包括—蓋板、一底板和一設於該蓋板 與該底板之間之側壁，且該葉輪位於該蓋板、底板和 該側壁所圍成之空間内。該側壁上設有一出風口和一 與該出風口臨近之舌部。該蓋板上設有一第一入風口 和-位於該第一入風口内之突起，該底板上設有一臨 近該舌部之通風孔。 '本發明之離心風扇在第—入風口内設置突起，可 減小第-人風π内之進風量，從而減少多餘風量在舌 部處之擾動，進而降低噪音；此外，在離心風扇舌部 附近設通孔’可以及時排除在此處擠壓堆積之多餘風 量，從而降低噪音。 【實施方式】 請參閱圖丄及圖2,分別為本發明一較佳實施例 之離心風扇之立體組合圖及分解圖，該離心風扇可與 200920948 一散熱裝置（圖未示）組合用於對發熱電子元件散熱。 - 該離心風扇包括一扇框100以及一收容於該扇框 • 100内之葉輪200。該葉輪200包括一輪轂220及由該 輪轂220周邊向外呈放射狀延伸之複數葉片240，該 等葉片240呈順時針方向傾斜，且葉片240端部呈逆 時針方向彎曲。 該扇框100包括一蓋板120、一底板140和一設 於該蓋板120與該底板140之間之側壁160。其中， 該側壁160係從該底板140周緣向上延伸形成之半封 閉結構，其包括一弧狀面16 2和一直面16 4。在該側 壁160上開設一出風口 180，接近於該出風口 180處 在該弧狀面162上設置一舌部190，該舌部190由外 向内突出並伸入到該出風口 180内。 該蓋板120可拆卸地安裝在該側壁160上並令該 葉輪200設於該蓋板120、底板140和該侧壁160圍 成之空間内。 該蓋板120之形狀與底板140之形狀相似，該蓋 板120中間開設一第一入風口 122，而該底板140上 設有一第二入風口 142。在該蓋板120上形成有一位 於該第一入風口 122内之突起124，該突起124從第 一入風口 122的内緣朝向第一入風口 122的中心方向 延伸而形成。該突起124臨近該舌部190並伸入該第 一入風口 122内，使得該第一入風口 122正對該舌部 190處之面積減小，從而減少該第一入風口 122内之 9 200920948 進風量，特別係臨近該舌部190處之進風量，進而降 - 低該離心風扇之噪音。 - 工作時，該葉輪200帶動周圍氣流一起旋轉，外 界氣流從該蓋板120上之第一入風口 122及該底板 140上之第二入風口 142進入該扇框100内，隨著葉 片240轉動，該扇框100内之氣流從出風口 180處排 出。由於在該蓋板120上臨近該舌部190處設置突伸 於該第一入風口 122内之突起124，使從該處進入之 氣流減少，從而減少在舌部190處堆積之多餘氣流， 進而降低由於多餘氣流在該舌部190處受擠壓擾動而 引起之嗓音。 在上述實施例中，該突起124臨近該舌部190 ; 在實際使用過程中，也可令該突起設置在遠離該舌部 處以減少第一入風口處之進風量，也可在一定程度上 降低離心風扇之噪音。 為進一步降低該離心風扇之噪音，可以在該底板 \' 140上設置二個通孔148。如圖2所示，該通孔148 呈橢圓形，位於舌部190與葉片240端部之間，且該 通孔148靠近舌部190並沿弧狀面162之弧向並列配 置。該通孔148之數量和形狀可根據具體實施方案而 變更，但位置要設在底板140上，且臨近舌部190。 葉片240與舌部190之間之多餘氣流可通過該通孔 148及時排出，從而防止氣流在舌部190處堆積擾動， 進而降低噪音。 10 200920948 為更進一步降低該離心風扇之噪音，可以在該底 板140上設置一位於該第二入風口 142内之擋板 144。如圖2所示，該擂板144臨近該舌部190並與該 蓋板120上之突起124上下相對，且令該通孔148位 於該擋板144與該舌部190之間。通過該擋板144， 可減少該第二入風口 142内之進風量，特別係臨近該 舌部190處之進風量，進而降低該離心風扇之噪音。 綜上所述，本發明中通過在蓋板120和底板140 上分別設置突起124和擋板144，可降低該第一入風 口 122及該第二入風口 142内之進風量，從而減少在 舌部19 0處堆積之多餘氣流，進而降低由於多餘氣流 在該舌部190處受擠壓擾動而引起之噪音；再者，通 過在該底板140上設置通孔148，可將葉片240與舌 部190之間之多餘氣流及時排出，從而防止氣流在舌 部190處堆積擾動，進一步降低嚼音。 綜上所述，本發明符合發明專利之要件，爰依法 提出專利申請。惟以上所述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】 圖1係本發明離心風扇一較佳實施例之立體組合 圖。 圖2係圖1中離心風扇之立體分解圖。 π 200920948 圖3係背景技術中一離心風扇之立體分解圖。 【主要元件符號說明】 扇框 100 蓋板 120 第一入風口 122 突起 124 底板 140 第二入風口 142 擋板 144 通孔 148 側壁 160 弧狀面 162 直面 164 出風口 180 舌部 190 葉輪 200 輪轂 220 葉片 240 12200920948 IX. Description of the invention: 'Technical field to which the invention pertains. The present invention relates to a centrifugal fan, and more particularly to a centrifugal fan having a lower noise. • [Prior Art] When, with the rapid development of the computer industry, heat generated by heat-generating electronic components such as chips in notebook computers is increasing. In order to effectively dissipate the excess heat, a heat sink is usually disposed on the surface of the heat-generating electronic component, and then a centrifugal fan is disposed on the heat sink, and the cooling airflow generated by the centrifugal fan is used to forcibly dissipate the heat sink. The heat generated by the heat-generating electronic components is dissipated. Since the size of the airflow generated by the fan depends on the fan speed, in order to further improve the performance of the fan, the fan rotation rate must be increased. However, an increase in the fan speed will cause a significant increase in the noise generated by the fan, and the user located near the centrifugal fan may feel uncomfortable or even unbearable. As shown in FIG. 3, a centrifugal fan includes a frame and an impeller 2 〇 received in the frame 10. The fan frame 1 is provided with a first air inlet 12 and a second air inlet respectively on the top surface and the bottom surface. 14. A tongue portion 16 is formed inwardly from the side wall adjacent to the air outlet. The impeller 20 is provided with a plurality of blades 26 on the outer circumference of the hub 22. The wheel 20 is further connected with a disk 24, and the disk 24 is attached to the blade 26 The end of the blade 26 is located on the upper side of the blade 26, and since the blade 26 is closest to the tongue 16, when the wind enters from the first air inlet 12 and the second air inlet 14, it will generate excess in the tongue 16. The excess air volume, such as the hai, is disturbed at the tongue 16 and causes a squeak. SUMMARY OF THE INVENTION It is necessary to provide a centrifugal fan with lower noise. > A centrifugal fan includes a fan frame and an impeller housed in the frame. The fan frame is provided with a first air inlet, an air outlet and a tongue adjacent to the air outlet. Wherein, the fan frame is provided with a protrusion located in the first air inlet, and the protrusion is adjacent to the tongue. ^ - a kind of fan from the d, including a fan frame and an impeller housed in the fan frame. The sea fan frame includes a cover plate, a bottom plate and a side wall disposed between the cover plate and the bottom plate, and the impeller Located in the space enclosed by the cover, the bottom plate and the side wall. The side wall is provided with an air outlet and a tongue adjacent to the air outlet. The cover plate is provided with a first air inlet and a protrusion located in the first air inlet, and the bottom plate is provided with a ventilation hole near the tongue. The centrifugal fan of the present invention provides protrusions in the first air inlet to reduce the amount of air entering the first person's wind π, thereby reducing the disturbance of the excess air volume at the tongue, thereby reducing noise; in addition, the tongue of the centrifugal fan The through hole near the 'can eliminate the excess air volume squeezed here to reduce the noise. [Embodiment] Please refer to FIG. 2 and FIG. 2, respectively, a perspective assembled view and an exploded view of a centrifugal fan according to a preferred embodiment of the present invention. The centrifugal fan can be combined with a heat sink (not shown) of 200920948 for Heated electronic components dissipate heat. - The centrifugal fan comprises a frame 100 and an impeller 200 housed in the frame 100. The impeller 200 includes a hub 220 and a plurality of vanes 240 extending radially outwardly from the periphery of the hub 220. The vanes 240 are inclined in a clockwise direction and the ends of the vanes 240 are curved in a counterclockwise direction. The frame 100 includes a cover 120, a bottom plate 140, and a side wall 160 disposed between the cover 120 and the bottom plate 140. The side wall 160 is a semi-closed structure extending upward from the periphery of the bottom plate 140, and includes an arcuate surface 16 2 and a straight surface 16 4 . An air outlet 180 is defined in the side wall 160. A tongue 190 is disposed on the curved surface 162 near the air outlet 180. The tongue 190 protrudes from the outside and protrudes into the air outlet 180. The cover plate 120 is detachably mounted on the side wall 160 and the impeller 200 is disposed in the space surrounded by the cover plate 120, the bottom plate 140 and the side wall 160. The shape of the cover plate 120 is similar to that of the bottom plate 140. A first air inlet 122 is defined in the middle of the cover plate 120, and a second air inlet 142 is defined in the bottom plate 140. A protrusion 124 formed in the first air inlet 122 is formed in the cover plate 120, and the protrusion 124 is formed to extend from the inner edge of the first air inlet 122 toward the center of the first air inlet 122. The protrusion 124 is adjacent to the tongue 190 and extends into the first air inlet 122 such that the area of the first air inlet 122 is reduced toward the tongue 190, thereby reducing the number 9 in the first air inlet 122. The amount of incoming air, in particular, is adjacent to the amount of air entering the tongue 190, which in turn lowers the noise of the centrifugal fan. - During operation, the impeller 200 rotates the surrounding airflow together, and the external airflow enters the fan frame 100 from the first air inlet 122 on the cover 120 and the second air inlet 142 on the bottom plate 140, as the blade 240 rotates The airflow in the fan frame 100 is discharged from the air outlet 180. Since the protrusion 124 protruding from the first air inlet 122 is disposed adjacent to the tongue 190 on the cover 120, the airflow entering from the portion is reduced, thereby reducing excess airflow accumulated at the tongue 190, and further The arpeggio caused by the squeezing of the excess airflow at the tongue 190 is reduced. In the above embodiment, the protrusion 124 is adjacent to the tongue 190; during actual use, the protrusion may be disposed away from the tongue to reduce the amount of air entering the first air inlet, or may be reduced to some extent. The noise of the centrifugal fan. To further reduce the noise of the centrifugal fan, two through holes 148 may be provided in the bottom plate \' 140. As shown in Fig. 2, the through hole 148 is elliptical and is located between the tongue 190 and the end of the blade 240, and the through hole 148 is disposed adjacent to the tongue 190 and juxtaposed along the arc of the arcuate surface 162. The number and shape of the through holes 148 can vary depending on the particular embodiment, but is located on the base plate 140 and adjacent the tongue 190. Excess airflow between the blade 240 and the tongue 190 can be expelled through the through hole 148 in time to prevent airflow from accumulating at the tongue 190, thereby reducing noise. 10 200920948 To further reduce the noise of the centrifugal fan, a baffle 144 located in the second air inlet 142 may be disposed on the bottom plate 140. As shown in FIG. 2, the seesaw 144 is adjacent to the tongue 190 and is vertically opposed to the protrusion 124 on the cover 120, and the through hole 148 is located between the baffle 144 and the tongue 190. Through the baffle 144, the amount of air entering the second air inlet 142 can be reduced, in particular, the amount of air entering the tongue 190, thereby reducing the noise of the centrifugal fan. In summary, in the present invention, by providing protrusions 124 and baffles 144 on the cover 120 and the bottom plate 140 respectively, the amount of air entering the first air inlet 122 and the second air inlet 142 can be reduced, thereby reducing the amount of the tongue. The excess airflow accumulated at the portion 19, thereby reducing the noise caused by the squeeze of the excess airflow at the tongue 190; further, by providing the through hole 148 in the bottom plate 140, the blade 240 and the tongue can be Excess airflow between 190 is expelled in time to prevent airflow build-up at the tongue 190, further reducing chewing. In summary, the present invention conforms to the requirements of the invention patent, and proposes a patent application according to law. The above description is only the preferred embodiment of the present invention, and equivalent modifications or variations made by those skilled in the art of the present invention should be included in the following claims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective assembled view of a preferred embodiment of a centrifugal fan of the present invention. 2 is an exploded perspective view of the centrifugal fan of FIG. 1. π 200920948 Fig. 3 is an exploded perspective view of a centrifugal fan in the background art. [Main component symbol description] Fan frame 100 Cover 120 First air inlet 122 Projection 124 Base plate 140 Second air inlet 142 Baffle 144 Through hole 148 Side wall 160 Arc surface 162 Straight surface 164 Air outlet 180 Tongue 190 Impeller 200 Hub 220 Blade 240 12