机械工程专业英语ppt

1、Lesson 21 LubricationMembers: 钱钰钱钰 尹珍尹珍 杨静杨静 王丽平王丽平 刘文玲刘文玲 高玉雪高玉雪 李园园李园园 Lesson 21 Lubrication定义：在两摩擦表面间加入润滑剂，形成润滑膜，而起到降低摩擦、减轻磨损和散热降温的作用-这种方法称为润滑。知识回顾：润滑知识回顾：润滑Lesson 21 Lubrication知识回顾：润滑的种类知识回顾：润滑的种类按摩擦副之间润滑材料的不同，润滑可分为流体按摩擦副之间润滑材料的不同，润滑可分为流体（液体、气体）润滑和固体润滑（液体、气体）润滑和固体润滑按摩擦副之间摩擦状态的不同，润按摩擦副之间摩擦状态的不同，

2、润滑又分为流体润滑和边界润滑。介滑又分为流体润滑和边界润滑。介于流体润滑和边界润滑之间的润滑于流体润滑和边界润滑之间的润滑状态称为混合润滑。状态称为混合润滑。Lesson 21 Lubrication知识回顾：润滑剂的作用知识回顾：润滑剂的作用a. 润滑作用：减少摩擦、降低磨损；b. 冷却作用：润滑剂在循环中将摩擦热带走，降低温度防止烧伤；c. 洗涤作用：从摩擦面上洗净污秽，金属粉粒等异物；d. 密封作用：防止水分和其他杂物进入；e. 防锈防蚀：使金属表面与空气隔离开，防止氧化；f. 减震卸荷：对往复运动机件有减震、缓冲、降低噪音的作用，压力润滑系统有使设备启动时卸荷和减少起动力矩的作用；g.

3、 传递动力：在液压系统中，油是传递动力的介质。Lesson 21 Lubrication为了改善润滑润滑性能，在某些润滑剂中可加入合适的添加剂。选用润滑剂时，一般须考虑摩擦副的运动情况、材料、表面粗糙度、工作环境和工作条件，以及润滑剂的性能等多方面因素。在机械设备中，润滑剂大多通过润滑系统输配给各需要润滑的部位。 The fluid may be introduced intentionally as the oil in the main bearings of an automobile , or unintentionally , as in the case of water betw

4、een a smooth rubber tire and a wet pavement这种流体可能是有意引入的，例如像汽车主轴承中的润滑油；这种流体可能是有意引入的，例如像汽车主轴承中的润滑油；也可能是无意中引入的，例如在光滑的橡胶轮胎与潮湿的路面也可能是无意中引入的，例如在光滑的橡胶轮胎与潮湿的路面之间的水之间的水in the case of adv在在.的情况下的情况下in case of adv假设，万一假设，万一Lesson 21 LubricationLesson 21 LubricationIf the lubricating films pressure is supplied

5、by an external source , the system is said to be lubricated hydrostatically 如果润滑膜的压力是由外源供给的，这种系统就称为流体静压润滑如果润滑膜的压力是由外源供给的，这种系统就称为流体静压润滑1 1If the pressure between the surfaces is generated as a result of the shape and motion of the surefaces themselves , the system is hydrodynamically lubricated如果滑动表面

6、之间的压力是由于滑动面本身的形状和运动所共同产生的，这种系统就称为流体动压润滑2 2Boundary lubrication Boundary lubrication 边界润滑边界润滑 A condition that lies between A condition that lies between unlubricatedunlubricated sliding and sliding and fluid-film lubrication is fluid-film lubrication is referred to as boundary referred to as boundar

7、y lubrication. lubrication. 处以无润滑滑动和流体膜润滑之间处以无润滑滑动和流体膜润滑之间的状态被称为边界润滑。的状态被称为边界润滑。 Solid lubricationSolid lubrication固体润滑固体润滑 Solids such as graphite and molybdenum disulfide are widely used when normal lubricants do not possess sufficient resistance to load or temperature extremes. 当普通润滑剂没有足够的承受载荷当普通

8、润滑剂没有足够的承受载荷的能力或者不能在温度极限下工作的能力或者不能在温度极限下工作时，石墨和二硫化钼这一类固体润时，石墨和二硫化钼这一类固体润滑剂得到广泛的应用。滑剂得到广泛的应用。Friction contrloThe amount and character of the lubricant made available to sliding surfaces have a profound effect upon the friction that is encountered.滑动面之间润滑剂的数量和性质对所产生的摩擦力有极大的影响。have a effect upon 对有影响控制

9、摩擦力磨损控制Wear Wear controlcontrolThey reduce abrasiveabrasive and solid-to-solid contact wear by providing a film that increases the distance between the sliding surfaces, thereby lessening the damage by abrasive contaminantscontaminants and surface asperitiesasperities. .润滑剂通过润滑膜来增加滑动面之间的距离，从而减轻磨料污染物

10、和表面凹凸不平造成的损伤，因此减轻了磨蚀和由固体与固体之间接触造成的磨损。Lesson 21 LubricationFunctions of lubricants. Temperature control: Lubricants assist in controlling temperature by reducing friction and carrying off the heat that is generated. Effectiveness depends upon the amount of lubricant supplied, the ambient temperature,

11、and the provision for external cooling.To a lesser extent,the type of lubricant also affects surface temperature.Functions of lubricants.Functions of lubricants.when machinery is in use,the lubricant controls corrosion by coating lubricated parts with a protective film that may contain additives to neutralize corrosive materials.coating涂料，包衣additives添加剂neutralize抵消，中和.Other functions:1.Power transmission（传递动力）（传递动力）2.Insulation（绝缘）（绝缘）3.Shock dampening（减震）（减震）4.Sealing（密封）（密封）Lubri