200844345 九、發明說明： 暴 譫 » ' 【發明所屬之技術領域】 - 本發明涉及輛承結構，特別涉及一種動壓軸承結構及 • 使用該動㈣承結構之散熱風扇。 【先前技術】 +目軸承廣泛應用於各種設備中，尤其是動壓轴承 在龟子衣置中使用知更加晋遍，如硬碟驅動器、數位化視 _ 頻光碟機、微型光碟機、磁光碟機及散熱風扇等領域，該 等衣置中馬達之軸承尺寸小，對轴承之回轉精度及壽命要 求南。 動壓軸承係在轉軸與軸承間之微小間隙内形成一層流 體(可為氣體或液體)潤滑油膜，潤滑油通過流經木同斷面積 之剪力作用而產生一動壓效果，使得該動壓軸承以高剛性 對轉軸進行支承及潤滑，從而使得轉轴與轴承不直接接 觸’可減少磨損、降低噪音，並可提升轴承使用壽命。 φ 現今通常在軸承之内表面上設置複數具有一定幾何形 狀之動壓溝槽，當轴承與轉軸高速相對運轉時產生動壓效 果。然而目前之動壓溝槽其幾何形狀複雜，並且由於軸承 之微型化趨勢使得轴承内徑相對地縮小，使得加工成型該 等動壓溝槽非常困難，難以提高產品之良率與生產效率。 而且由於該等動壓溝槽之幾何形狀不具有對稱性，轴承產 生動壓效果受到轉轴運轉時一定轉向之限定，從而在組袋 時必須考慮其特定之方向性，影響到組裝之效率，給生產 帶來極大之不便。 6 200844345 【發明内容】 y 有鑒於此，有必要提供一種加工簡便且易於組裝之無 方向性動壓軸承結構及一種採用該動壓轴承結構之散熱風 扇。 一種動壓軸承結構，包括一動壓軸承，該動壓軸承之 内表面上沿軸向形成複數動壓溝槽，每一動壓溝槽具有兩 個動壓面，該兩動壓面互相對稱，其橫截面呈V形。 一種動壓軸承結構，包括一轉轴，該轉轴之外表面上 沿軸向形成複數動壓溝槽，每一動壓溝槽具有兩個動壓 面，該兩動壓面互相對稱，其橫截面呈V形。 一種散熱風扇，包括底座、軸承結構、定子構件及轉 子構件，該軸承結構包括一固定於底座中央之動壓軸承， 該轉子構件包括一轉軸，該轉軸穿設於動壓軸承之軸孔 内，該動壓軸承之内表面上與轉轴之外表面上其中之一凹 陷形成複數動壓溝槽，每一動壓溝槽具有兩個動壓面，該 兩動壓面沿過軸孔之中心與兩動壓面之交線所形成之平面 呈對稱分佈。 與習知動壓軸承結構相比，上述動壓轴承結構在動壓 軸承或轉軸上沿轴向形成多個結構對稱之動壓溝槽，使得 加工簡便，且組裝上不受方向之限制，提高了生產效率。 【實施方式】 請參閱圖1至圖3,該實施例中，以一散熱風扇為例說 明動壓軸承結構，顯然該動壓軸承結構還可應用於硬碟驅 動器等用馬達作為驅動源之裝置中。該散熱風扇主要包括 200844345200844345 IX. Description of the invention: violent 谵 » 'Technical field to which the invention pertains - The present invention relates to a bearing structure, and more particularly to a dynamic bearing structure and a cooling fan using the moving (four) bearing structure. [Prior Art] + eye bearing is widely used in various equipments, especially dynamic pressure bearings are used in the turtle suits, such as hard disk drives, digital video recorders, micro CD players, magneto-optical discs. In the fields of machines and cooling fans, the size of the bearings of these motors is small, and the requirements for the rotation accuracy and life of the bearings are south. The dynamic pressure bearing forms a fluid (may be gas or liquid) lubricating oil film in a small gap between the rotating shaft and the bearing, and the lubricating oil generates a dynamic pressure effect by the shearing force flowing through the same area of the wood, so that the dynamic pressure bearing Supporting and lubricating the shaft with high rigidity, so that the shaft and the bearing are not in direct contact' can reduce wear, reduce noise, and improve bearing life. φ Nowadays, a plurality of dynamic pressure grooves having a certain geometric shape are usually arranged on the inner surface of the bearing, and a dynamic pressure effect is generated when the bearing and the rotating shaft are relatively operated at a high speed. However, the current dynamic pressure groove has a complicated geometry, and the inner diameter of the bearing is relatively reduced due to the miniaturization of the bearing, making it difficult to process the dynamic pressure grooves, and it is difficult to improve the yield and production efficiency of the product. Moreover, since the geometry of the dynamic pressure grooves is not symmetrical, the dynamic pressure effect of the bearing is limited by the certain steering when the rotating shaft is running, so that the specific directivity must be considered when assembling the bag, which affects the efficiency of assembly. It brings great inconvenience to production. 6 200844345 [Disclosed Summary] In view of the above, it is necessary to provide a non-directional dynamic pressure bearing structure which is easy to process and easy to assemble, and a heat radiating fan using the dynamic pressure bearing structure. A dynamic pressure bearing structure comprises a dynamic pressure bearing, wherein a plurality of dynamic pressure grooves are formed on an inner surface of the dynamic pressure bearing, each dynamic pressure groove has two dynamic pressure surfaces, and the two dynamic pressure surfaces are symmetrical to each other. The cross section is V-shaped. A dynamic pressure bearing structure includes a rotating shaft, and a plurality of dynamic pressure grooves are formed on an outer surface of the rotating shaft, each dynamic pressure groove has two dynamic pressure surfaces, and the two dynamic pressure surfaces are symmetrical with each other The cross section is V-shaped. A cooling fan includes a base, a bearing structure, a stator member and a rotor member. The bearing structure includes a dynamic pressure bearing fixed to a center of the base, the rotor member includes a rotating shaft, and the rotating shaft is disposed in a shaft hole of the dynamic pressure bearing. The inner surface of the dynamic pressure bearing and one of the outer surfaces of the rotating shaft are recessed to form a plurality of dynamic pressure grooves, each dynamic pressure groove has two dynamic pressure surfaces, and the two dynamic pressure surfaces are along the center of the shaft hole The plane formed by the intersection of the two moving faces is symmetrically distributed. Compared with the conventional dynamic pressure bearing structure, the dynamic pressure bearing structure has a plurality of structurally symmetric dynamic pressure grooves formed on the dynamic pressure bearing or the rotating shaft in the axial direction, so that the processing is simple and the assembly is not restricted by the direction, and the assembly is improved. Production efficiency. [Embodiment] Please refer to FIG. 1 to FIG. 3 . In this embodiment, a dynamic heat-dissipating fan is taken as an example to illustrate a dynamic pressure bearing structure. It is obvious that the dynamic pressure bearing structure can also be applied to a device such as a hard disk drive using a motor as a driving source. in. The cooling fan mainly includes 200844345
一底座70、設於底座7〇上之定子構件60、轉子構件3〇、 動壓軸承10及軸套20。 底座7〇王圓盤形，其中央向上凸設有一軸座71，車由座 =頂端為一開口，中央形成一收容空間72用於嵌設軸套 ^疋子構件60包括電路板601及電樞602,其中電樞6〇2 見連接至該電路板6〇1，從而獲得電流以產生交變礤場。 〇轉子構件3〇包括—輪轂32，該輪轂32外緣玫射狀突 叹複數扇葉34，輪轂32内侧緣貼設一磁鐵環36。—轉軸 38其上端固定於該輪轂32中央，並向下延伸。轉輛3【在 接近其自由端之外表面上形成一環形凹槽384。 —轴套20為圓筒形，其底端封閉，上端開口，内部步 二個容置空間209。在轴套20之内壁於靠近盆底端^山 形成一階梯部2。2'2。4(圖3)，其中階梯部二 k大於階梯部202之内徑，因而容 ㈣後大小不同之圓柱形㈣，且從心 到頂端，該三個圓枉形空間之直徑依 之底端 m H 曰大。一圓形之斛 β片50即放置在容置空間209之底部 之耐 兮即階梯部202之丁 u亥耐磨片50之直徑與容置空間209底部 下， 好容置該耐磨片50。該風扇工作時，耐磨片/才目同因而剛 之自由端相抵靠，可避免轉軸38與輛套5〇與轉軸38 擦，從而提高軸套20之使用壽命。 之底端產生摩 動壓軸承10收容在容置空間2〇9肉、，职 η亚置於站卷0 階梯部202上。請一併參閱圖4與圖5，& 之 動壓軸承1〇内部 8 200844345 * 形成一軸孔11，以供轉軸38穿設延伸。動壓轴承/10之外 - 表面上形成四個回油槽12，與動壓軸承10之軸孔11相連 通’以供潤滑油回流。該等回油槽12均勻對稱地分佈在動 # 壓軸承之外表面上。任一回油槽12包括兩第一部分 121 ’分別位於動壓軸承ι〇之兩末端之表面上，一第二部 分122位於動壓軸承1〇之外圓周表面上。請參圖5，該等 回油槽12之橫截面為半圓形，實際上回油槽也可以為 _ 其他形狀，只要能達到回流潤滑油之功效即可。動壓軸承 10之内表面上沿軸向形成複數動壓溝槽14,其數量可根據 實際需要而作相應變化，該實施例中為三個，且這三個動 壓溝槽14在動壓軸承1〇之内表面上呈均勻分佈，其中一 動壓溝槽14與動壓軸承1〇之外表面上之一回油槽12直接 對正而相連通，這樣有利於潤滑油從動壓軸承1〇外回流到 動壓軸承10内。每一動壓溝槽14之截面呈v形，其具有 兩個對等之動壓面141、142，該兩動壓面141、142面積相 φ 等，且沿過軸孔11之中心與兩動壓面141、142之交線所 形成之平面呈對稱分佈。兩動壓面141、142可為斜面，也 可為其他形狀簡單、易於加工之曲面如弧面等，圖5中所 示之兩動壓面141、142為斜面，且該兩動壓面141、142 與動壓軸承10之内表面之圓弧面相切。該實施例中，動壓 溝槽14之深度w，即動壓溝槽14之最深處145與未形成 動壓溝槽時該動壓轴承1 〇之假想内圓周在徑向方向上之距 離，最好為〇·〇6毫米至0·1毫米之間，以便形成具最佳動 壓效果之油膜層。動壓溝槽14之該深度w可因動壓轴承 9 200844345 10之尺寸不同而作相應調整。動壓軸承10之内外表面於其 兩端分別形成圓弧倒角，這樣便於轉轴38以及動壓軸承10 之裝設。 一擔油環40設置在容置空間2〇9之頂端處並抵靠在軸 套20之階梯部204上。該擋油環40之外徑與軸套20之頂 知内在大小基本相同，因而能充分封住該頂端開口。擋油 環40中心設有一穿孔42 (圖1)以供轉軸38穿設延伸， 該穿孔42之直徑略大於轉軸之外徑，雨者之間形成一 較小間隙。該風扇工作時，此較小間隙不至於使潤滑油洩 漏至擋油環40之外，又可以避免擋油環4〇和轉軸38之間 產生摩擦。 該風扇組裝時，將轴套20之底端嵌設固定在底座70 之收容空間72内，轴套20外緣固裝定子構件6〇，耐磨片 50置於軸套20内之容置空間209之底部，動壓軸承1〇收 谷於軸套20之谷置空間209内並抵靠在轴套2〇内之階梯 部202上，動壓轴承1〇之頂端在軸套2〇内之階梯部2〇4 之下。動壓軸承10之底端與耐磨片50之間有一定之間距。 轉軸38旋轉地收容於動壓軸承1〇之軸孔u内，轉軸38 外表面上之環形凹槽384可在轉軸38運轉時減少轉軸38 與動壓軸承10之接觸面積，並形成一存油空間。擋油環40 套設於轉軸38上，收容於軸套20之容置空間2〇9内並抵 靠在階梯部204上，擋油環40之頂端與軸套2〇之頂端大 致平齊，檔油環40之底端與動壓軸承10之頂端間隔一定 之間距，動壓軸承10、擋油環40與軸套20三者之間共同 200844345 . 形成一儲油空間，該儲油空間與軸孔11連通。 / . 該風扇工作時，定子構件60和轉子構件30在磁場之 ’ 交互作用下驅動轉軸38旋轉。由於動壓軸承10之内表面 上形成有動壓溝槽14，轉軸38高速運轉時，可在動壓溝槽 14處形成動壓效果，儲存於其内之潤滑油可在轉轴38之外 表面與動壓軸承10之内表面之間形成一層油膜，使該油膜 層對轉轴38進行支承及潤滑，從而使得轉軸38與動壓轴 承10不直接接觸，以減小摩擦，降低噪音。同時由於離心 ® 力作用，潤滑油會沿著轉軸38與動壓轴承10内表面之間 之間隙向上爬升，並暫存在動壓軸承10、擋油環40與軸套 20共同形成之儲油空間内，最後可沿著動壓軸承10之外表 面上之回油槽12回流到動壓軸承10之底部而繼續重複利 用。 由於動壓軸承10内表面之動壓溝槽14其截面呈對稱 之V形結構，轉軸38在動壓溝槽14處形成之動壓效果不 ^ 受轉軸38旋轉方向之限制，因而在裝配動壓轴承10時， 不必考慮其方向性，從而能提高組裝效率。同時，因為動 壓軸承10内之動壓溝槽14呈簡單之兩動壓面對稱結構， 加工製作簡便，極大地提高了生產效率。 上述實施例中之散熱風扇僅在動壓軸承10之内表面上 形成動壓溝槽14,實際上也可單獨或同時在轉轴38之外表 面上軸向形成多個動壓溝槽，該等動壓溝槽均勻地分佈在 轉軸38之外表面上。請參考圖6與圖7，在轉軸38之外表 面上凹陷形成動壓溝槽386時，每一動壓溝槽386也具有 11 200844345 上述實施财祕料14相同之結構，具有_對等之動 壓面387、388，該兩動璧面3δ7、娜之面積相等·， 呈v形，且該兩動壓面387、388沿通過轉轴处之中心與 兩動壓面387、388之交靖张犯a、七丁 ^ 麵軸之平面呈轉分佈。圖6 與圖7中所示之兩動壓面38? ^ ^ ^ ㈤387 388為斜面，與上述實施例 中之動壓面141、142 —样▲叮达社 k也可為其他形狀簡單、易於加工 之曲面如弧面等。 專利=所^本發明符合發料利之要件，練法提出 ^ 上所4者僅為本發明讀佳實施例，舉凡 人士’在爰依本發明精神所作之等效修飾 【圖式簡單說明】 曱，專利乾圍内。 圖1為本發明動壓軸承結構之較佳實施例使用於散熱 風扇之立體分解圖。 圖2為圖1之組合立體圖。 參 圖3為圖2沿則1線之剖面示意圖。 圖4為圖1中動壓軸承之放大示意圖。 圖5為圖4之俯視圖。 圖6為本發明動壓軸承結構另—實施例中轉軸之立 示意圖。 【主ΐΐί圖/沿VII_Vn線之剖面示意圖。 L主要兀件付號說明】 11 121 回油槽 12 動壓轴承U) 軸孔 第一部分 12 200844345 第二部分 122 動壓溝槽 14 ✓ 動壓面 141 、 142 動壓溝槽最深處 145 軸套 20 階梯部 202 > 204 容置空間 209 轉子構件 30 輪轂 32 扇葉 34 磁鐵環 36 轉軸 38 環形凹槽 384 擋油環 40 穿孔 42 耐磨片 50 定子構件 60 電路板 601 電柩 602 底座 70 軸座 71 收容空間 72 13A base 70, a stator member 60 disposed on the base 7A, a rotor member 3A, a dynamic pressure bearing 10, and a sleeve 20. The base 7 has a disc shape, and a shaft seat 71 is protruded upward from the center. The seat is a seat and the top end is an opening. The center forms a receiving space 72 for embedding the sleeve. The latch member 60 includes a circuit board 601 and electricity. A pivot 602 in which the armature 6〇2 is connected to the circuit board 6〇1 to obtain an electric current to generate an alternating field. The cymbal rotor member 3 includes a hub 32, the outer edge of which swells a plurality of blades 34, and a magnet ring 36 is attached to the inner edge of the hub 32. - The shaft 38 has its upper end fixed to the center of the hub 32 and extends downward. The swivel 3 [forms an annular groove 384 on the outer surface near its free end. The sleeve 20 has a cylindrical shape, the bottom end of which is closed, the upper end is open, and the inner step is two accommodating spaces 209. A step portion 2 is formed on the inner wall of the sleeve 20 near the bottom end of the basin. 2'2. 4 (Fig. 3), wherein the step portion 2k is larger than the inner diameter of the step portion 202, and thus the cylindrical shape is different in size. (d), and from the heart to the top, the diameter of the three circular domes is larger by the bottom end m H . A circular cymbal β sheet 50 is placed under the bottom of the accommodating space 209 at the bottom of the accommodating space 209, and has a diameter and a bottom of the accommodating space 209, so as to accommodate the wear-resistant sheet 50. . When the fan is in operation, the wear piece/the eye is abutted against the free end of the sleeve, so that the shaft 38 and the sleeve 5〇 and the shaft 38 are prevented from rubbing, thereby improving the service life of the sleeve 20. At the bottom end, the friction bearing 10 is housed in the accommodating space 2〇9 meat, and the η is placed on the station roll 0 step portion 202. Please refer to FIG. 4 and FIG. 5 together with the dynamic pressure bearing 1 inside. 8 200844345 * A shaft hole 11 is formed for the shaft 38 to extend. Outside the dynamic pressure bearing/10 - Four oil return grooves 12 are formed on the surface, and are connected to the shaft hole 11 of the dynamic pressure bearing 10 for returning the lubricating oil. The oil return grooves 12 are uniformly and symmetrically distributed on the outer surface of the movable bearing. Each of the oil return grooves 12 includes two first portions 121' on the surfaces of the two ends of the dynamic pressure bearing ι, and a second portion 122 on the outer circumferential surface of the dynamic pressure bearing 1''. Referring to Figure 5, the oil return groove 12 has a semi-circular cross section. In fact, the oil return groove can also be _ other shapes as long as the effect of the reflux lubricating oil can be achieved. A plurality of dynamic pressure grooves 14 are formed on the inner surface of the dynamic pressure bearing 10 in the axial direction, and the number thereof can be correspondingly changed according to actual needs. In this embodiment, three, and the three dynamic pressure grooves 14 are in the dynamic pressure shaft. The inner surface of the bearing is uniformly distributed, and one of the dynamic pressure grooves 14 is directly aligned with the oil return groove 12 on the outer surface of the dynamic pressure bearing 1〇, which is beneficial to the lubricating oil from the dynamic pressure bearing 1〇. The outside is returned to the dynamic pressure bearing 10. Each of the dynamic pressure grooves 14 has a v-shaped cross section, and has two equal dynamic pressure surfaces 141 and 142. The two dynamic pressure surfaces 141 and 142 have an area φ and the like, and are movable along the center of the shaft hole 11 and the two movements. The plane formed by the intersection of the pressing faces 141, 142 is symmetrically distributed. The two dynamic pressure surfaces 141 and 142 may be inclined surfaces, or may be other curved surfaces that are simple in shape and easy to be processed, such as curved surfaces. The two dynamic pressure surfaces 141 and 142 shown in FIG. 5 are inclined surfaces, and the dynamic pressure surfaces 141 are 141. And 142 are tangent to the arc surface of the inner surface of the dynamic pressure bearing 10. In this embodiment, the depth w of the dynamic pressure groove 14 is the distance between the deepest portion 145 of the dynamic pressure groove 14 and the imaginary inner circumference of the dynamic pressure bearing 1 在 in the radial direction when the dynamic pressure groove is not formed, It is preferably between 6 mm and 0. 1 mm to form an oil film layer having an optimum dynamic pressure effect. The depth w of the dynamic pressure groove 14 can be adjusted correspondingly depending on the size of the dynamic pressure bearing 9 200844345 10 . The inner and outer surfaces of the dynamic pressure bearing 10 are respectively formed with circular chamfers at both ends thereof, which facilitates the mounting of the rotating shaft 38 and the dynamic pressure bearing 10. A slinger 40 is disposed at the top end of the accommodating space 2〇9 and abuts against the step 204 of the sleeve 20. The outer diameter of the slinger 40 is substantially the same as the inner diameter of the sleeve 20, so that the top opening can be sufficiently sealed. The center of the oil slinger 40 is provided with a through hole 42 (Fig. 1) for extending through the shaft 38. The diameter of the hole 42 is slightly larger than the outer diameter of the shaft, and a small gap is formed between the rainers. When the fan is in operation, this small gap does not allow the lubricating oil to leak out of the slinger 40, and friction between the slinger 4 and the shaft 38 can be avoided. When the fan is assembled, the bottom end of the sleeve 20 is embedded and fixed in the receiving space 72 of the base 70. The outer edge of the sleeve 20 is fixed to the stator member 6〇, and the wear piece 50 is placed in the receiving space in the sleeve 20. At the bottom of the 209, the dynamic pressure bearing 1 is received in the valley space 209 of the sleeve 20 and abuts against the step portion 202 in the sleeve 2, and the top end of the dynamic pressure bearing 1 is in the sleeve 2 Below the step 2〇4. There is a certain distance between the bottom end of the dynamic pressure bearing 10 and the wear piece 50. The rotating shaft 38 is rotatably received in the shaft hole u of the dynamic pressure bearing 1〇. The annular groove 384 on the outer surface of the rotating shaft 38 can reduce the contact area between the rotating shaft 38 and the dynamic pressure bearing 10 when the rotating shaft 38 is operated, and form an oil retaining body. space. The oil slinger 40 is sleeved on the rotating shaft 38, and is received in the accommodating space 2〇9 of the sleeve 20 and abuts against the stepped portion 204. The top end of the slinger 40 is substantially flush with the top end of the sleeve 2〇. The bottom end of the oil ring 40 is spaced apart from the top end of the dynamic pressure bearing 10 by a certain distance, and the dynamic pressure bearing 10, the oil retaining ring 40 and the sleeve 20 are jointly formed by 200844345. An oil storage space is formed, and the oil storage space is The shaft holes 11 are in communication. When the fan is in operation, the stator member 60 and the rotor member 30 drive the shaft 38 to rotate under the interaction of the magnetic field. Since the dynamic pressure groove 14 is formed on the inner surface of the dynamic pressure bearing 10, when the rotating shaft 38 is operated at a high speed, a dynamic pressure effect can be formed at the dynamic pressure groove 14, and the lubricating oil stored therein can be outside the rotating shaft 38. An oil film is formed between the surface and the inner surface of the dynamic pressure bearing 10, so that the oil film layer supports and lubricates the rotating shaft 38, so that the rotating shaft 38 and the dynamic pressure bearing 10 are not in direct contact to reduce friction and reduce noise. At the same time, due to the centrifugal force, the lubricating oil will climb upward along the gap between the rotating shaft 38 and the inner surface of the dynamic pressure bearing 10, and temporarily store the oil storage space formed by the dynamic pressure bearing 10, the oil retaining ring 40 and the sleeve 20 together. Finally, the oil return groove 12 on the outer surface of the dynamic pressure bearing 10 can be returned to the bottom of the dynamic pressure bearing 10 to continue the reuse. Since the dynamic pressure groove 14 on the inner surface of the dynamic pressure bearing 10 has a symmetrical V-shaped cross section, the dynamic pressure effect formed by the rotating shaft 38 at the dynamic pressure groove 14 is not limited by the rotation direction of the rotating shaft 38, and thus is assembled. When the bearing 10 is pressed, it is not necessary to consider its directivity, so that assembly efficiency can be improved. At the same time, since the dynamic pressure groove 14 in the dynamic pressure bearing 10 has a simple two-dynamic symmetrical structure, the processing is simple and the production efficiency is greatly improved. The heat dissipating fan in the above embodiment forms the dynamic pressure groove 14 only on the inner surface of the dynamic pressure bearing 10, and actually, a plurality of dynamic pressure grooves can be axially formed on the outer surface of the rotating shaft 38 separately or simultaneously. The equal dynamic pressure grooves are evenly distributed on the outer surface of the rotating shaft 38. Referring to FIG. 6 and FIG. 7, when the dynamic pressure groove 386 is recessed on the outer surface of the rotating shaft 38, each dynamic pressure groove 386 also has the same structure as the above-mentioned implementation of the financial material 14, and has _ equivalent movement. The pressing faces 387, 388, the two moving faces 3δ7, the area of the Na are equal, and are v-shaped, and the two moving faces 387, 388 pass along the center of the rotating shaft and the two moving faces 387, 388 Zhang made a, seven Ding ^ plane of the plane axis is turned. The dynamic pressure surface 38? ^ ^ ^ (5) 387 388 shown in Fig. 6 and Fig. 7 are inclined surfaces, and the dynamic pressure surfaces 141 and 142 in the above embodiment are similar to each other. The curved surface is curved, etc. The invention is in accordance with the requirements of the invention, and the practice of the invention is only a preferred embodiment of the invention, and the equivalent modification of the person in the spirit of the invention [simple description of the schema] , the patent is within the perimeter. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective exploded view of a preferred embodiment of a dynamic pressure bearing structure for use in a heat dissipating fan. Figure 2 is a perspective view of the combination of Figure 1. Figure 3 is a schematic cross-sectional view taken along line 1 of Figure 2. Figure 4 is an enlarged schematic view of the dynamic pressure bearing of Figure 1. Figure 5 is a plan view of Figure 4. Fig. 6 is a perspective view showing the shaft of another embodiment of the dynamic pressure bearing structure of the present invention. [Main ΐΐί diagram / schematic diagram of the section along the VII_Vn line. L main components payment instructions] 11 121 oil return groove 12 dynamic pressure bearing U) shaft hole first part 12 200844345 second part 122 dynamic pressure groove 14 ✓ dynamic pressure surface 141, 142 dynamic pressure groove deepest 145 sleeve 20 Step portion 202 > 204 accommodating space 209 rotor member 30 hub 32 blade 34 magnet ring 36 shaft 38 annular groove 384 oil slinger 40 perforation 42 wear plate 50 stator member 60 circuit board 601 electric 602 base 70 shaft seat 71 Containing space 72 13