sleevebearings

1、第八章 Sleeve bearings 滑動軸承81 General considerations 概述 82 Materials of sleeve bearings (materials of bearing shells and inserts) 滑動軸承材料（軸瓦及軸承襯材料）83 Simplified calculations for bearings operating with non-fluid friction 非液體摩擦軸承設計計算84 Load-carrying mechanics of the hydrodynamic lubrication bearings 液體動壓

2、潤滑軸承承載機理81 general considerations 概概述述2） 液體摩擦軸承Loads are beard completely by irregularities (boundary friction) 載荷全由微峰承擔（邊界摩擦）Loads are beard commonly by irregularities and oil film (載荷由微峰和油膜共同承擔（混合摩擦）2） Fluid friction bearings： 液體摩擦軸承Loads are beard completely by oil film 載荷全由油膜承擔Hydrostatic pressu

3、re 靜壓Hydrodynamic pressure 動壓Three kinds of different sliding friction conditionsII With respect to load-carrying direction 按承載方向分：按承載方向分：1） Thrust bearings 推力軸承：FA2） Radial bearings 向心軸承：FrRadial bearings 向心軸承：FrSolid bearings :used for low speed and light load shaft (the clearance in the bearing c

4、an not be adjusted and it is difficult to assembly) 整體式：低速輕載（間隙不可調，安裝困難）Split bearings: common application 剖分式：一般應用Solid radial sleeve bearingbushinghousingOil holeSolid shellSplit radial sleeve bearingBearing supportBearing capSplit shellsStud-boltSplit shells2、 Shortcomings High starting torque 起動

5、阻力大1、Advantages Operating steady , reliably and noiselessly 工作穩(wěn)定、可靠、無噪音 Under fluid friction, friction and wear are small and oil film has a marked damping effect 液體摩擦時，摩擦、磨損小，油膜吸振 二、 Characteristics and applications 特點和應用3、 Applications 應用應用 Shafts running at exceptionally high speeds or requiring

6、high-precision guidance or carrying heavy load （fluid friction bearings） 高速、重載、精密（液體摩擦滑動軸承） Shafts running at low speed noncritical mechanisms （ non-fluid friction bearings ） 低速、輕載、精度要求低時（非液體摩擦滑動軸承） Special occasion：for example, split shell is required or operating in aggressive media. 特殊場合:如必須剖分或者宇

7、航、探海等三、三、 Contents of the chapter 本章內容本章內容 Selection of the bearing materials 軸承材料選擇 Design of non-fluid friction bearings 非液體摩擦滑動軸承設計計算 Load-carrying mechanics of the hydrodynamic lubrication bearings 液體摩擦軸承承載原理82 Materials of sleeve bearings （ materials of bearing shells and inserts ） 滑動軸承材料（軸瓦及軸承

8、襯材料）Bearing shell: Element contacting directly with journal軸瓦：軸承直接與軸頸相接觸的零件 Bearing insert: thin layer which is adhered on bearing shell by casting or pressuring in. 軸承襯：有的軸瓦是在軸瓦整體上用澆鑄或壓合的方法粘附上一層另一種材料，這一薄層材料稱為軸承襯。一、 Requirements for bearing materials： Small friction coefficient, good heat conductivi

9、ty and low linear expansion coefficient (efficiency high, stable dimension and small temperature increase operating ) 摩擦系數(shù)小，導熱性好，熱膨脹系數(shù)小 （效率高、尺寸穩(wěn)定、溫升?。?High wear resistance, good corrosion resistance and anti-seizing 耐磨、耐蝕和抗膠合性好Enough mechanical strength （ anti-impact, anti-press and anti-fatigue）（pr

10、event from press and fatigue failures ） 足夠機械強度（沖擊、抗壓、疲勞） （避免壓潰和疲勞破壞） Capacity for being run in readily and low modules of elasticity 一定順應性和嵌藏性順應性：適應軸偏斜的能力 減小偏載嵌藏性：容納異物的能力 避免軸頸傷和磨損（彈性模量小塑性增加順應性和嵌藏性好） Good processing properties, such as castability, manufacturability, etc 良好的工藝性（容易鑄造和加工）.1、軸承合金（白合金、巴氏

11、合金） babbitts based on tin 錫銻軸承合金：ZChSnSb116 based on lead 鉛銻軸承合金：ZChPbSb16162Advantages：Small friction coefficient and high anti-seizing Used for high speed and heavy load 摩擦系數(shù)小，抗膠合性好用于高速、重載Shortcomings： High cost and low strength Used for bearing inserts 價格高、強度低用作軸承襯 二、Major bearing materials 常用材料2

12、、 Bronzes 軸承青銅 Tin bronzes 錫磷青銅：ZCuSn10P1 Leaded bronzes 錫鋅鉛青銅：ZCuSn5Pb5Zn5 Aluminum-iron bronzes 鋁鐵青銅： ZCuAl9Fe4Ni4Mn2Advantages：High strength, high wear resistance and good thermal conductivity. Used for bearing shell and inserts 強度高、耐磨性好、導熱性好，即可用于 軸瓦，又可以作軸承襯3、 Brass: used for low speed and medium

13、 load 黃銅：低速中載4、Cast iron: used for low speed and light load 鑄鐵：低速輕載5、Bearings filled with oil 含油軸承:Sintered metal powders 粉末冶金材料Porous structure、 Filled with oil Self-lubrication多孔、含油自潤滑Bad roughness 韌性差Used for steady load and places which is difficult or impossible to lubricate 平穩(wěn)無沖擊、難于用油潤滑處Iron-g

14、raphite Fe石墨Bronze-graphite Cu石墨6、 Plastics 軸承塑料軸承塑料vAdvantages：small friction coefficient, self-lubrication and low modules of elasticity 摩擦系數(shù)小，自潤滑性和嵌藏性好vShortcomings：bad heat-resistance and low thermal conductivity. When they absorb moisture, sizes expansion takes place. Otherwise, under common lo

15、ad, dramatic deformation will take place in plastics bearings . 耐熱性、導熱性差，吸水膨脹，易變形常用作軸承襯 三、Structures of bearing shell 軸瓦結構Bearing inserts are used 加軸承襯1、 Bearing shells 軸瓦 Single metal shell 單金屬軸瓦 Double metals shell 雙金屬軸瓦 Three metals shell 三金屬軸瓦2、Oil hole, oil groove and oil chamber 油孔、油溝、油室油孔、油溝、

16、油室 Oil hole 油孔 For supplying oil 供油 Oil groove 油溝Conveying oil 輸送油Distributing oil 分布油Equispacing oil 均布油Reserving oil 貯油Steadily supplying oil 穩(wěn)定供油 Oil chamber 油室Oil grooves are cut in zones where there are not force or there are smaller force in order to supply oil easily and prevent from reduce l

17、oad-carrying ability at same time. 油溝開于不受力或者受力較小區(qū)，以利供油，同時避免降低承載能力83 非液體摩擦軸承設計計算一、Types of failures and design criteria 失效形式和設計準則 Wear boundary film do not lose 磨損邊界膜不破裂 This has many affecting factors and analyses are considerably complicated simplified calculation 因素多，復雜條件性計算 F d B Radial bearings

18、徑向軸承：徑向軸承： Average pressure is limited （ prevent from oil to be force out ） 限制平均壓強（防油擠出過度磨損） ppMPapdBFp只校核低速或間歇轉動軸承，Only check pp for low speed or pause rotating bearings pv is limited: （ prevent from excessive temperature increasing oil film lose excessive wear）限制限制pv值值 （防溫升（防溫升t過大過大油膜油膜破裂破裂過度磨損）過度

19、磨損） m/sMPapv2000F100060dBFpv1BnndTvv m/s （ Prevent from excessive speed quick wear）（p較小時）（防較小時）（防v過大過大加速磨損）加速磨損）v100060vdnp、pv、vP161表91 Thrust bearings 推力軸承 ：油環(huán)數(shù)Zm/sMPapvZdd0003FnpvMPpZdd4Fpm/sMPapvpvMPapp0202（液體軸承起動、停車：混和摩擦狀態(tài)）84 Load-carrying mechanics of the hydrodynamic lubrication bearings 液體動壓潤

20、滑軸承承載機理一、Basic equation of hydrodynamic lubrication-Reynolds equation （1886年）液體動壓潤滑基本方程 雷諾方程（雷諾方程）30hhhV6xp1、 Assumptions 假設假設 Compared with forces of viscous shear, inertia and gravity of the fluid are very small and are neglected 與粘滯阻力相比， 流體慣性力、重力很小，忽略 Flow of lubricant belong to laminar flow 潤滑油為

21、層流流動yv服從牛頓剪切定律：Forces of viscous shear developed in the layers can be determined by Newtons law of viscous flow. Sliding do not exist between lubricant and planes 潤滑劑與板面無滑動 The dimensions in the direction perpendicular to the drawing are assumed to be infinitely large 軸承無限寬（Z向無流動）Viscosity and densi

22、ty of the oil do not depend on pressure 流體粘度、密度與壓力無關2、Introduction 推導By means of： Equilibrium equation of the oil 流體平衡方程 Newtons law of viscous flow 牛頓內摩擦定律Principle of continuity of flow 流體流動連續(xù)性方程yv0 xqxReynolds equation 雷諾方程流體平衡方程0Fx）（假設1.yxp0dy)dxdzy(dx)dydzxp(pdxdzpdydz Newtons law of viscous fl

23、ow牛頓內摩擦定律（假設牛頓內摩擦定律（假設2）.yvxpyv22By integrating twice and substituting the boundary conditions 積分積分xp2)()(vVChVxp21C0vhyVv0y3CyCyxp21vxp1.yv2121222yhyhyhV、：由假設xp122dyxp2)()(vdyq43h0h0 xhVhyhyhyhV無側漏）：量（假設面單位寬度面積上的流單位時間內流經(jīng)任一剖The volume of oil flowing per second through a clearance of height h and unit width is (side leakage do not exist) By means of principle of co