201120319 六、發明說明： 【發明所屬之技術領域】 [0001]本發明涉及一種風扇模組，尤係涉及一種用於對發熱電 子元件散熱之風扇模組及使用該風扇模組之散熱裝置。 【先前技術】 [0002] 隨著電子產業之快逮發展，電子元件（如中央處理器等 )之高速、高頻及集成化使其發熱量劇增，為了在有限 之空間内高效地帶走電子元件所產生之熱量，業界通常 會在電子元件上加裝一散熱裝置。 ❹ [0003] 該散熱裝置通常包括一散熱器及一風扇，該風扇設置於 該散熱器上並向該散熱器提供低溫氣流，該風扇具有一 轉子’該轉子包括一輪轂及設於該輪毅外圍之複數扇葉 ’當該風扇運轉時，由於該輪轂之存在，流向該散熱器 . 正對該輪轂之下方區域即該散熱器之中部之氣流較少， 容易在散熱器之中部形成空流區域，而電子元件通常設 於散熱器之中部，這就使得集中在散熱器中部之熱量不 〇 能及時有效地散發出去。 【發明内容】 [0004] 有鑒於此，有必要提供一種可提高散熱效率之風扇模組 及使用該風扇模組之散熱裝置。 [0005] —種風扇模組，包括一主風扇’該主風扇包括一轉子， 該轉子包括一輪轂及設於該輪較外圍之複數扇葉，該風 扇模組還包括一輔風扇，該輔風扇設於該主風扇之輪轂 下方，該輔風扇包括一轉子，該輔風扇之轉子包括—輪 0982070759-0 季又及ό史於该輪數外圍之複數扇葉，該輔風扇之扇苹靠近 098141252 表單編號Α0101 第5頁/共18頁 201120319 輔風扇之輪轂之内側端在該主風扇之轉子之經向上位於 該主風扇之輪轂之内，該輔風扇之扇葉遠離輔風扇之輪 較之外側端在該主風扇之轉子之徑向上延伸至該主風^ 之輪轂之外，該輔風扇之扇葉在該主風扇產生之氣、充之 直接推動下旋轉並產生氣流。 [0006] [0007] 一種散熱裝置’包括一散熱器及設於該散熱器上之— 風 扇模組，該風扇模組包括一主風扇，該主風扇包括—轉 子，該轉子包括一輪轂及設於該輪轂外圍之複數扇葉，201120319 VI. Description of the Invention: [Technical Field] The present invention relates to a fan module, and more particularly to a fan module for dissipating heat from a heat-generating electronic component and a heat sink using the same. [Prior Art] [0002] With the rapid development of the electronics industry, the high-speed, high-frequency and integration of electronic components (such as central processing units) has caused a rapid increase in heat generation, in order to efficiently take away in a limited space. For the heat generated by electronic components, the industry usually installs a heat sink on the electronic components. 0003 [0003] The heat sink generally includes a heat sink and a fan, the fan is disposed on the heat sink and provides a low temperature airflow to the heat sink, the fan has a rotor, the rotor includes a hub and is disposed on the wheel The peripheral plurality of blades 'When the fan is running, due to the presence of the hub, it flows to the radiator. The area below the hub, that is, the middle of the radiator, has less airflow, and it is easy to form an air flow in the middle of the radiator. The area, and the electronic components are usually placed in the middle of the radiator, so that the heat concentrated in the middle of the radiator can be dissipated in a timely and effective manner. SUMMARY OF THE INVENTION [0004] In view of the above, it is necessary to provide a fan module capable of improving heat dissipation efficiency and a heat sink using the same. [0005] A fan module includes a main fan. The main fan includes a rotor. The rotor includes a hub and a plurality of blades disposed on a periphery of the wheel. The fan module further includes a auxiliary fan. The fan is disposed under the hub of the main fan, and the auxiliary fan includes a rotor, and the rotor of the auxiliary fan includes a wheel 0982070759-0 and a plurality of blades on the periphery of the wheel, the fan of the auxiliary fan is close to 098141252 Form No. Α0101 Page 5 of 18 201120319 The inner end of the hub of the auxiliary fan is located in the hub of the main fan in the warp direction of the rotor of the main fan, and the fan blade of the auxiliary fan is away from the wheel of the auxiliary fan. The outer end extends outside the rotor of the main fan in the radial direction of the main fan, and the fan blade of the auxiliary fan rotates under the direct force of the gas generated by the main fan to generate airflow. [0007] A heat dissipating device 'includes a heat sink and a fan module disposed on the heat sink, the fan module includes a main fan, the main fan includes a rotor, and the rotor includes a hub and a rotor a plurality of blades on the periphery of the hub,
5 玄風扇模組還包括一輔風扇，該輔風扇設於該主風屢 輪轂下方’該輔風扇包括-轉子，該輔風扇之轉子包括 -輪轂及設於該輪轂外圍之複數扇¥，_風扇之:葉 靠近輔風扇之輪轂之内側端在魅風备之轉子之徑= 位於該主風扇之輪較之内，該輔風扇之扇葉遠離輔風 之輪較之外側端在該主風扇之轉子之徑向上延伸至^ 風扇之輪轂之外，該輔風扇之扇葉在該主風扇產生: 流之直接推動下旋轉並產生氣流。 *The fan module further includes an auxiliary fan disposed under the main wind wheel hub. The auxiliary fan includes a rotor, and the rotor of the auxiliary fan includes a hub and a plurality of fans disposed on the periphery of the hub. Fan: the inner end of the leaf near the hub of the auxiliary fan is in the diameter of the rotor of the charm wind = in the wheel of the main fan, the fan blade of the auxiliary fan is away from the auxiliary wind wheel than the outer side end of the main fan The rotor extends radially beyond the hub of the fan, and the fan blades of the auxiliary fan rotate under the direct drive of the main fan to generate airflow. *
上述風扇模減㈣該 扇設於該域狀輪^下方，且 工稀風 葉靠近純之内側端在該主風扇之轉子之徑向上位= 主風扇之輪轂之内，而遠雜 . 讀糾之相端在該主風扇之 轉子之徑向上延伸至該主風 風扇之輪轂之外，該輔風扇内 不需設置定子及磁組，該輔e 孩輔風扇之轉子在該主風扇產生 之氣流之直接推動下旋轉， 〇〇 亚產生吹向該散熱器之氣流 :’、、、讀於主風扇之輪較下方之熱量能夠及時有 效地散發出去’有利於提高散熱效率。 098141252 表單編號A0101 第6頁/共18頁 0982070759-0 201120319 【實施方式】 [0008]下面參照附圖結合實施例對本發明作進一步說明。 闺®1所不為本發明第―實施例中之散熱裝置，該散熱裝置 用於對一發熱電子元件1〇散熱，該散熱裝置包括一散熱 器20及設於該散熱器2〇上之一風扇模組3〇。 [0W0]該散熱器20包括一底板21及由該底板21垂直向上延伸之 複數散熱鰭片23，該底板21之下表面之中央貼設於該發 熱電子元件10上，該等散熱鑛片23平行排列，每相鄰之 Ο 兩散熱鰭片23間形成一氣流通道231，該等散熱鰭片23中 位於中央之部分之南度小於位於外緣之部分之高度，從 而於該散熱器2 0頂端之中部形成一凹陷2 3 2。 [0011]該風扇模組3 0包括一主風扇31及設於該主風扇3丨下方之 一輔風扇33，該主風扇31與輔風扇33均為轴流風扇。 [0012] 請參照圖2 ’該主風扇31包括一扇框311、一軸承系統 313、固定於該扇框311上之一定子315及罩設於該定子 315上之一轉子317。 [0013] 該扇框^11固定於該散熱器20位於外緣之散熱鰭片23上， 該扇框311呈方形環狀，其上、下兩端分別形成一入風口 3111及一出風口 3112，該扇框311底端之中央設有一基 板3113，該基板3113藉由複數支撐肋（圖未示）連接於 該扇框311上’該出風口 3112形成於該等支撐肋之間，該 基板3113之中央向上凸伸一中空之中柱3114，該中柱 3114之頂端開口。 [0014] 該軸承系統313收容於該中柱3114内，該軸承系統313包 0982070759-0 098141252 表單編號A0101 第7頁/共18頁 201120319 括一軸承3131及設於該軸承3131下方之一扣環3132，該 軸承31 31呈中空圓柱狀，該扣環31 32呈環狀。 [0015] 該定子31 5包括一電路板31 51及固定於該電路板31 51上 之一線圈組3152 ’該電路板3151與線圈組3152環設於該 扇框311之中柱3114之外圍。 [0016] 該轉子317罩設於該定子315之線圈組3152之外圍，該轉 子317包括一輪轂3171、一轉軸3172、複數扇葉3173及 一磁組3174。該輪轂3171呈中空之半封閉狀，其包括一 圓形之端部31 75及自該端部3.1 75之周緣垂直向下延伸之 一筒狀側壁3176。該轉軸3172之頂端固定於該輪轂3171 之端部3175之内側面之中央，該轉轴3172之中部設於該 軸承3131内，其底端可旋轉地扣接於該扣環3132上。該 等扇葉3173環設於該輪轂3171之侧壁3176之外圍。該磁 組3174貼設於該輪轂3171之侧壁3176之内表面上。 [0017] 該輔風扇33設於該主風扇31之輪轂3171之正下方，並收 容於該散熱器20頂端之凹陷232内，該輔風扇33包括一扇 框331、一軸承系統333及一轉子337。 ¥ [0018] 該扇框331固定於該散熱器20位於中部之散熱鰭片23上， 該扇框1 31之外徑小於該主風扇31之扇框311之外徑，該 扇框3 31亦呈方形環狀’其上、下兩端分別形成一入風口 3311及一出風口 3312，該扇框331底部之中央設有一基 板3313 ’該基板3313藉由複數支樓肋（圖未示）連接於 該扇框331上，該出風口 3312形成於該等支撐肋之間，該 基板3313之中央向上凸伸一中空之中柱3314，該中柱 098141252 表單編號A0101 第8頁/共18頁 0982070759- 201120319 [0019] [0020] Ο ο [0021] 3314之頂端開口。 該軸承系統333與該主風扇31之軸承系統313相同，該轴 承系統333亦包括一轴承3331及一扣環3332 ° 該轉子337罩設於該扇框331之中柱3314之外圍，該轉子 33?包括一輪轂3371、一轉轴3372及複數扇葉3373。該 輪轂3371之外徑小於該主風扇31之輪轂3171之外徑’該 輪轂3371亦包括一圓形之端部3375及自該端部3375之周 緣垂直向下延伸之一筒狀侧壁3376。該轉軸3372之結構 及位置關係與該主風扇31之轉軸3172結構及位置關係相 同。該等扇葉3373環設於該輪轂3371之側壁3376之外圍 ，該等扇葉3373靠近輪轂3371之内侧端在該主風扇31之 轉子317之徑向上位於該主風扇.3..1_之輪穀31_71之内’而 遠離輪轂3371之外侧端在該主風扇31之轉子317之徑向 上延伸至該主風扇31之輪轂3171之外，以保證該主風扇 31產生之氣流能夠吹到該辅風扇33之扇葉3373伸出該主 風扇31之輪轂3171之外之部位上，從而推動該輔風扇33 之轉子337旋轉。 工作時’該風扇模組3〇之主風扇31開始運轉，該主風扇 31之轉子317之屬葉3173產生之靠外側之一部分氣流經 由該主風扇31底端之出風口 3112吹向該散熱器20位於外 緣之放熱韓片23，並進入對應之氣流通道231内，從而與 δ亥散熱器20進行熱交換’該主風扇31之轉子317之扇葉 3173產生之靠内側之一部分氣流經由該主風扇31底端之 098141252 出風口 3丨12及該輔風扇33頂端之入風口 3311進入該輔風 扇33内’並吹向該輔風扇33之扇葉3373，從而推動該輔 表單編據Α0101 第9頁/共18頁 0982070759-0 201120319 風扇33之轉子337旋轉，該輔風扇33之轉子337旋轉產生 之氣流經由該輔風扇33底端之出風口 3312吹向該散熱器 20位於中部之散熱鰭片23，並進入對應之氣流通道231内 ，從而與散熱器20之中部進行熱交換。 [0022] [0023] 上述散熱裝置中，該輔風扇33設於該主風扇31之轉子317 之輪轂3171之下方，且該輔風扇33之轉子337之扇葉 3373靠近輪轂3371之内側端在該主風扇3丨之轉子317之 徑向上位於該主風扇31之輪轂3171之内，而遠離輪轂 3371之外側端在該主風扇31之轉子317之徑向上延伸至 該主風扇31之輪轂3171之外，該輔風扇33之轉子337在 該主風扇31產生之氣流之直接推動下旋轉，並產生吹向 該散熱器20中部之氣流，使該散熱器20之中部高度集中 之熱量能夠及時有效地散發出去，可防止設於該散熱器 20底部中央之發熱電子元件1〇因過熱而損毀，有利於提 高發熱電子元件1〇之壽命。另外，由於該輔風扇33之轉 子337係在該主風扇31產生之氣流之推動下旋轉，故，該 輔風扇33内無需設置定子及磁組，相對於該主風扇31之 轉子317之輪轂3171，該輔風扇33之輪轂3371之尺寸較 小’其遮擋該散熱器2〇之面積亦相對較小，有利於減少 該主風扇31之輪轂3171下方形成之空流區域之面積，提 高散熱裝置之散熱效率。 圖3所示為本發明第二實施例之風扇模組3〇3，與第一實 知*例中之風扇模組30不同之是：該風扇模組30a中之輔風 扇33a並未設置扇框，該輔風扇33a之軸承系統333a收容 於該轉子337a之輪轂3371a内，且該輔風扇33a之轴承系 098141252 表單編號A0101 第10頁/共18頁 0982070759-0 201120319 Ο [0024] Ο [0025] [0026] 統333a之輛承333丨a結合於該轉子337a之輪轂3371 a之 内表面上，該輔風扇33a之轉轴3372a之頂端固定於該主 風扇31之基板Μα之中央，.並與該主風扇31之轉轴3172 同軸，該輔風扇33a之轉軸33728之中部設於該軸承系統 333a之轴承gggia内5其底端扣接於該轴承系統333a之 扣環3332a上，使該輔風扇33a之轉子337a與軸承系統 333a可旋轉地固定於轉軸3372a上。工作時，該主風扇 31之轉子317之扇葉3173產生之靠内側之一部分氣流進 入該輔風扇33a内，並吹向該輔風扇33a之扇葉3373a， 從而推動該輔風扇33a之轉子337a與轴承系統333a繞著 该轉轴3372a旋轉，該輔風.扇::.33a之轉子337a旋轉產生之 氣流直接吹向該散熱器20位於中部之散熱韓片23。 . .... . ..... : 上述風扇模組3〇a中，由於其輔風扇33a並未設置扇框， 该輔風扇33a之轉子337a之輪轂3371a内並未設置扇框上 之中柱’相對於第一實施例中之輔風扇33之轉子337之輪 較3371 ’本實施例中之輔風扇33a之輪穀3371a之尺寸更 小，其遮擋該散熱器2〇之面積亦相對更小，可進一步減 少該主風扇31之輪轂3171下方形成之空流區域之面積， 提高散熱裝置之散熱效率。 鉍上所述，本發明符合發明專利要件，爰依法提出專利 申清°惟’以上所迷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_請專利範圍内。 【圖式簡單說明】 圖1為本發明第—實施例之散熱裝置之剖面示意圖。 098141252 表單編號A0101 第11頁/共18頁 0982070759-0 201120319 [0027] 圖2為圖1所示散熱裝置中之風扇模組之放大示意圖 [0028] 圖3為本發明第二實施例之風扇模組之剖面示意圖 【主要元件符號說明】 [0029] 發熱電子元件：10 [0030] 散熱器：20 [0031] 底板：21 [0032] 散熱鰭片：23 [0033] 氣流通道：231 [0034] 凹陷：2 3 2 [0035] 風扇模組：30、30a [0036] 主風扇：31 [0037] 輔風扇：33、33a [0038] 扇框：311、331 [0039] 入風口 ： 3111、3311 [0040] 出風口 ： 3112、3312 [0041] 基板：3113、3313 [0042] 中柱：3114、3314 [0043] 轴承系統：313、3 3 3、3 3 3 a [0044] 軸承：3131、3331、3331a [0045] 扣環：3132、3332、3332a 098141252 表單編號A0101 第12頁/共18頁 0982070759-0 201120319 [0046] [0047] [0048] [0049] [0050] [0051] [0052] ❹ [0053] [0054] [0055] Ο 定子：315 電路板：3151 線圈組：31 5 2 轉子：317、337、337a 輪轂：3171、3371、3371a 轉軸：3172、3372、3372a 扇葉：3173、3373、3373a 磁組：3174 端部：3175、3375 側壁：3176、3376 098141252 表單編號A0101 第13頁/共18頁 0982070759-0The fan mold is reduced (4), the fan is disposed under the domain wheel ^, and the dirty blade is close to the pure inner end in the radial position of the rotor of the main fan = the hub of the main fan, and the miscellaneous. The phase end extends in the radial direction of the rotor of the main fan to the hub of the main fan, and the stator and the magnetic group are not disposed in the auxiliary fan, and the rotor of the auxiliary fan is in the airflow generated by the main fan. Directly pushing the lower rotation, the 〇〇亚 produces a flow of air that is blown toward the radiator: ',,, the heat that is read below the wheel of the main fan can be effectively and efficiently dissipated in a timely manner' to improve heat dissipation efficiency. 098141252 Form No. A0101 Page 6 of 18 0982070759-0 201120319 [Embodiment] [0008] The present invention will be further described below with reference to the accompanying drawings. The heat sink is not used for heat dissipation in the first embodiment of the present invention, and the heat sink is configured to dissipate heat from a heat-generating electronic component 1 . The heat sink includes a heat sink 20 and one of the heat sinks 2 Fan module 3〇. [0W0] The heat sink 20 includes a bottom plate 21 and a plurality of heat dissipation fins 23 extending vertically upward from the bottom plate 21, and a center of a lower surface of the bottom plate 21 is attached to the heat-generating electronic component 10, and the heat-dissipating iron pieces 23 Parallelly arranged, an air flow channel 231 is formed between each adjacent heat sink fin 23, and the south portion of the heat dissipation fins 23 is smaller than the height of the portion located at the outer edge, so that the heat sink 20 A recess 2 3 2 is formed in the middle portion of the tip end. The fan module 30 includes a main fan 31 and an auxiliary fan 33 disposed under the main fan 3, and the main fan 31 and the auxiliary fan 33 are both axial fans. [0012] Referring to FIG. 2, the main fan 31 includes a frame 311, a bearing system 313, a stator 315 fixed to the frame 311, and a rotor 317 disposed on the stator 315. [0013] The fan frame 11 is fixed on the heat sink fins 23 on the outer edge of the heat sink 20. The fan frame 311 has a square ring shape, and an upper air inlet 3111 and an air outlet 3112 are formed on the upper and lower ends. The bottom of the bottom of the fan frame 311 is provided with a substrate 3113. The substrate 3113 is connected to the fan frame 311 by a plurality of supporting ribs (not shown). The air outlet 3112 is formed between the supporting ribs. A central portion 3114 is protruded upward from the center of the 3113, and the top end of the center post 3114 is open. [0014] The bearing system 313 is received in the center pillar 3114. The bearing system 313 includes 0992070759-0 098141252 Form No. A0101 Page 7 of 18 201120319 includes a bearing 3131 and a buckle disposed under the bearing 3131 3132, the bearing 31 31 has a hollow cylindrical shape, and the buckle 31 32 has an annular shape. The stator 31 5 includes a circuit board 31 51 and a coil group 3152 ′ fixed to the circuit board 31 51. The circuit board 3151 and the coil group 3152 are disposed around the periphery of the column 3114 in the fan frame 311. [0016] The rotor 317 is disposed on the periphery of the coil assembly 3152 of the stator 315. The rotor 317 includes a hub 3171, a rotating shaft 3172, a plurality of blades 3173, and a magnetic group 3174. The hub 3171 has a hollow semi-closed shape and includes a rounded end portion 31 75 and a cylindrical side wall 3176 extending vertically downward from the periphery of the end portion 3.1 75. The top end of the rotating shaft 3172 is fixed to the center of the inner side surface of the end portion 3175 of the hub 3171. The middle portion of the rotating shaft 3172 is disposed in the bearing 3131, and the bottom end of the rotating shaft 3172 is rotatably fastened to the buckle 3132. The blades 3173 are disposed around the periphery of the side wall 3176 of the hub 3171. The magnetic group 3174 is attached to the inner surface of the side wall 3176 of the hub 3171. The auxiliary fan 33 is disposed directly under the hub 3171 of the main fan 31 and is received in the recess 232 at the top end of the heat sink 20. The auxiliary fan 33 includes a frame 331, a bearing system 333 and a rotor. 337. [0018] The frame 331 is fixed on the heat sink fin 23 of the heat sink 20, and the outer diameter of the fan frame 31 is smaller than the outer diameter of the fan frame 311 of the main fan 31. The upper and lower ends of the fan frame are respectively formed with an air inlet 3311 and an air outlet 3312. The center of the bottom of the fan frame 331 is provided with a substrate 3313. The substrate 3313 is connected by a plurality of branch ribs (not shown). In the fan frame 331, the air outlet 3312 is formed between the supporting ribs. The center of the substrate 3313 protrudes upwardly from a hollow middle pillar 3314. The center pillar 098141252 has the form number A0101 page 8 / 18 pages 0992070759- 201120319 [0019] [0021] The opening of the top end of 3314. The bearing system 333 is the same as the bearing system 313 of the main fan 31. The bearing system 333 also includes a bearing 3331 and a buckle 3332. The rotor 337 is disposed on the periphery of the column 3314 of the fan frame 331. The rotor 33 The utility model comprises a wheel hub 3371, a rotating shaft 3372 and a plurality of blades 3373. The outer diameter of the hub 3371 is smaller than the outer diameter of the hub 3171 of the main fan 31. The hub 3371 also includes a circular end 3375 and a cylindrical side wall 3376 extending vertically downward from the periphery of the end 3375. The structure and positional relationship of the rotating shaft 3372 are the same as the structure and positional relationship of the rotating shaft 3172 of the main fan 31. The fan blades 3373 are disposed at the outer periphery of the side wall 3376 of the hub 3371. The blades 3373 are located near the inner end of the hub 3371 in the radial direction of the rotor 317 of the main fan 31. The main fan is located at the main fan.3..1_ The inner side of the volute 31_71 and the outer side end of the main fan 31 extend outside the hub 3171 of the main fan 31 in the radial direction away from the hub 3371 to ensure that the airflow generated by the main fan 31 can be blown to the auxiliary The blade 3373 of the fan 33 projects beyond the hub 3171 of the main fan 31 to push the rotor 337 of the auxiliary fan 33 to rotate. During operation, the main fan 31 of the fan module 3 starts to operate, and a part of the airflow generated by the blade 3173 of the rotor 317 of the main fan 31 is blown toward the radiator through the air outlet 3112 at the bottom end of the main fan 31. 20 is located on the outer edge of the exothermic Korean film 23, and enters the corresponding airflow passage 231 to exchange heat with the delta heat sink 20. The fan airflow of the rotor blade 317 of the main fan 31 is generated by a portion of the inner airflow. The 906141252 air outlet 3丨12 at the bottom of the main fan 31 and the air inlet 3311 at the top end of the auxiliary fan 33 enter the auxiliary fan 33' and blow to the fan blade 3373 of the auxiliary fan 33, thereby pushing the auxiliary form file Α0101 9 pages/total 18 pages 0982070759-0 201120319 The rotor 337 of the fan 33 rotates, and the airflow generated by the rotation of the rotor 337 of the auxiliary fan 33 is blown toward the heat sink 20 through the air outlet 3312 at the bottom end of the auxiliary fan 33. The sheet 23 enters the corresponding air flow passage 231 to exchange heat with the middle portion of the heat sink 20. [0023] In the above heat dissipating device, the auxiliary fan 33 is disposed under the hub 3171 of the rotor 317 of the main fan 31, and the fan 3373 of the rotor 337 of the auxiliary fan 33 is adjacent to the inner end of the hub 3371. The main fan 3's rotor 317 is located radially inside the hub 3171 of the main fan 31, and the outer side away from the hub 3371 extends radially beyond the hub 3171 of the main fan 31 in the radial direction of the rotor 317 of the main fan 31. The rotor 337 of the auxiliary fan 33 rotates under the direct push of the airflow generated by the main fan 31, and generates a gas flow blowing toward the middle of the heat sink 20, so that the heat concentrated in the middle of the heat sink 20 can be efficiently and timely distributed. When it is taken out, the heat-generating electronic component 1 provided in the center of the bottom of the heat sink 20 is prevented from being damaged by overheating, which is advantageous for improving the life of the heat-generating electronic component. In addition, since the rotor 337 of the auxiliary fan 33 is rotated by the airflow generated by the main fan 31, there is no need to provide a stator and a magnetic group in the auxiliary fan 33, and the hub 3171 of the rotor 317 of the main fan 31 is provided. The size of the hub 3371 of the auxiliary fan 33 is smaller, and the area of the heat sink 2 is relatively small, which is advantageous for reducing the area of the air flow region formed under the hub 3171 of the main fan 31, thereby improving the heat dissipation device. Cooling efficiency. FIG. 3 shows a fan module 3〇3 according to a second embodiment of the present invention. The difference from the fan module 30 in the first embodiment is that the auxiliary fan 33a in the fan module 30a is not provided with a fan. The bearing system 333a of the auxiliary fan 33a is housed in the hub 3371a of the rotor 337a, and the bearing of the auxiliary fan 33a is 098141252. Form No. A0101 Page 10 of 18 page 0982070759-0 201120319 Ο [0024] Ο [0025 [0026] The bearing 333A of the system 333a is coupled to the inner surface of the hub 3371a of the rotor 337a, and the top end of the rotating shaft 3372a of the auxiliary fan 33a is fixed to the center of the substrate Μα of the main fan 31. Coaxial with the rotating shaft 3172 of the main fan 31, the rotating shaft 33728 of the auxiliary fan 33a is disposed in the bearing gggia 5 of the bearing system 333a, and the bottom end thereof is fastened to the buckle 3332a of the bearing system 333a, so that the auxiliary The rotor 337a of the fan 33a and the bearing system 333a are rotatably fixed to the rotating shaft 3372a. In operation, the fan 3173 of the rotor 317 of the main fan 31 generates a portion of the inner airflow into the auxiliary fan 33a, and blows toward the fan 3373a of the auxiliary fan 33a, thereby pushing the rotor 337a of the auxiliary fan 33a. The bearing system 333a rotates around the rotating shaft 3372a, and the airflow generated by the rotation of the rotor 337a of the auxiliary wind fan::33a is directly blown toward the heat radiating film 23 of the heat sink 20 in the middle. . . . . . . . : In the fan module 3〇a, since the auxiliary fan 33a is not provided with a fan frame, the hub 3371a of the rotor 337a of the auxiliary fan 33a is not provided with a fan frame. The middle column 'relative to the wheel 337 of the auxiliary fan 33 of the first embodiment is smaller than the 3371 'the valley 3371a of the auxiliary fan 33a in this embodiment, and the area of the radiator 2 遮 is relatively opposed. Smaller, the area of the air flow region formed under the hub 3171 of the main fan 31 can be further reduced, and the heat dissipation efficiency of the heat sink can be improved. As described above, the present invention complies with the requirements of the invention patents, and the patent application is stipulated in accordance with the law. However, the above is only a preferred embodiment of the present invention, and those skilled in the art of the present invention are made in accordance with the spirit of the present invention. Equivalent modifications or changes shall be covered by the following patents. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic cross-sectional view showing a heat dissipating device according to a first embodiment of the present invention. 098141252 Form No. A0101 Page 11/18 Page 0992070759-0 201120319 [0027] FIG. 2 is an enlarged schematic view of a fan module in the heat sink shown in FIG. 1 [0028] FIG. 3 is a fan mold according to a second embodiment of the present invention Schematic diagram of the group [Main component symbol description] [0029] Heated electronic component: 10 [0030] Heat sink: 20 [0031] Base plate: 21 [0032] Heat sink fin: 23 [0033] Air flow channel: 231 [0034] :2 3 2 [0035] Fan module: 30, 30a [0036] Main fan: 31 [0037] Auxiliary fan: 33, 33a [0038] Fan frame: 311, 331 [0039] Air inlet: 3111, 3311 [0040] ] Air outlet: 3112, 3312 [0041] Substrate: 3113, 3313 [0042] Middle column: 3114, 3314 [0043] Bearing system: 313, 3 3 3, 3 3 3 a [0044] Bearing: 3131, 3331, 3331a Buckle: 3132, 3332, 3332a 098141252 Form No. A0101 Page 12 / 18 pages 0992070759-0 201120319 [0046] [0049] [0050] [0052] [0052] 005 [0053] [0055] [0055] 定子 Stator: 315 Board: 3151 Coil set: 31 5 2 Rotor: 317, 337, 337a Hub: 3171, 3371, 3 371a Shaft: 3172, 3372, 3372a Fan blade: 3173, 3373, 3373a Magnetic group: 3174 End: 3175, 3375 Side wall: 3176, 3376 098141252 Form number A0101 Page 13 of 18 0982070759-0