机械设计4第四章摩擦磨损及润滑概述机械设计4第四章摩擦磨损及润滑概述.ppt

Friction force（摩擦力）——The force resisting the relative motion of solid surfa-ces, fluid layers, and material elements sli-ding against each other Wear（磨损）——The damage or transf-er of the material that is caused by someth-ing when it is being used normally I Basic concepts Lubrication（润滑）——The condition of having been made smooth or slippery by the applicat-ion of a lubricant such as oil or grease (脂) Tribology（摩擦学）——The branch of engineeri-ng that deals with the interaction of surfaces in relative motion (as in bearings or gears): their design and friction and wear and lubrication II Friction (摩擦) 1. Classification ①? Classified by whether two parts have relative movement Statical friction(静摩擦)——friction between two or more solid objects that are not moving relative to each other； Kinetic friction(动摩擦)——occurs when two objec-ts are moving relative to each other and rub together (like a sled(雪橇) on the ground). ②?Classified by movement type（important） Sliding friction（滑动摩擦）——occurs when two objects slide across from one another； Rolling friction (滚动摩擦)——occurs when a body (such as a ball, tire, or wheel) rolls on a surface. ③?Classified by lubricant （important） Dry friction (干摩擦)——resists relative lateral motion of two solid surfaces in contact Fluid friction（流体摩擦）——the friction between layers within a viscous fluid that are moving relative to each other； Boundary friction（边界摩擦）——occurs when a surface is at least partially wet, but not so lub-ricated that there is no direct friction between two surfaces; Mixed friction（混合摩擦）——a kind of friction including both boundary friction and fluid fric-tion. III Wear(磨损) Three stages of wear * run-in wear (磨合磨损) （useful） Stable wear (稳定磨损) （work） Severe wear (剧烈磨损) （failure） Wear rate ε：ε=△q ／ △t △q ——Wear magnitude Design or use a machine, you should do your best to reduce run-in time, increase stable wear time and postpone the arrival of severe wear. 1.Adhesive wear (粘着磨损) 3.Fatigue wear (疲劳磨损) Pressure—lo