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滚动轴承基础知识我国滚动轴承工业的发展概况什么是轴承：轴承是支撑轴或其它旋转件的零件;它引导旋转运动并承受传递给支架的负荷;滚动轴承与滑动轴承比较,由于其尺寸已经国际标准化,并且具有互换性好、维修方便、便于专业化大生产等特点,目前已发展成为现代化机械的重要精密配件之一,广泛的应用于汽车、拖拉机、机车车辆、船舶、飞机、雷达、机床、电机以及各种矿山、冶金、石化、轻纺、工程、地质、农机等机械、仪器仪表上;特别值得一提的是我国发射的神州五号载人飞船上,使用哈轴生产的九套轴承,哈轴的副总工程师、研究所所长等都参加了神州五号载人飞船发射成功的庆功、总结、表彰大会;我国的滚动轴承工业是解放后才建立并发展起来的,新中国成立以前,全国仅在瓦房店有一家轴承制造厂,其他在上海、沈阳、天津、长治等地仅有一些简陋的轴承修造点,大多数是手工作坊式的轴承修理厂,连最普通的球轴承都不能独立、完整的生产;新中国成立后,1950年抗美援朝,由于战备的需要,瓦房店轴承厂部分人员和设备搬迁到哈尔滨,建立了我国第二个轴承厂——哈尔滨轴承厂;在第一个五年计划期间,瓦房店轴承厂和哈尔滨轴承厂的部分人员和设备又搬迁到洛阳,新建了我国第三个轴承厂——洛阳轴承厂;从此我国有了三个大型的轴承企业,初步形成了我国轴承工业的基础;随着国民经济的发展和改革开放,先后在各省、市、自治区又建立了五十多个大中型主要生产厂家,再加上一些地方发展的小型企业全国已有轴承生产厂点近千个,基本上形成了我国轴承工业的生产体系;目前,我国各类轴承的总产量已超过五亿套,已能生产近四百种结构,一千多个尺寸系列,五千多个基本型号,两万多个品种,精度等级为P0、P6、P5、P4、P2的轴承;其中包括内径为㎜的微型轴承；外径达5000㎜、重量达的特大型轴承；套圈最小壁厚为㎜的薄壁柔性轴承以及高温、低温、高速、高真空、耐腐蚀、耐辐射等特殊工作条件下的轴承;有力的促进了国民经济的建设和国防工业的发展;一;轴承的概念轴承是支承轴或其它旋转件旋转,并能传递负荷的机器配件;滚动轴承是一种通用性很强、标准化程度很高的基础件,由于各种机械有着不同的工作条件和环境,对轴承在负荷能力、结构、使用性能等方面都提出了各种不同的要求,因此滚动轴承就需要有各式各样的结构来满足机械的要求,但其最基本的结构是由“四大件”组成的,即内圈、外圈、滚动体、保持器;（一）动轴承“四大件”在轴承中的作用及零件代号1．内圈内套：通常与轴紧配合,并一起旋转;代号：02；2．外圈外套：通常与轴承座孔配合,起支承作用;代号：01；3．滚动体钢球或滚子：借助保持架均匀地排列在内、外圈之间,其形状、大小和数量影响了轴承的承载能力和使用性能;代号：04;4．保持架：将滚动体均匀地分隔开,引导滚动体的旋转及改善轴承内部润滑性能; 代号：06实体,07冲压；5．推力轴承中与轴紧配合并一起旋转的叫轴圈,也叫紧圈；6．推力轴承中与轴承座孔配合的叫座圈,也叫活圈;二滚动轴承套圈的生产过程棒料→锻造→退火→车加工→热处理→磨加工→精研或抛光→零件终检→防锈入库;（三）球轴承的装配过程零件退磁、清洗→内、外圈滚道尺寸分组选别→合套→检查游隙→铆合保持架→终检→退磁清洗→涂油、包装→入成品库装箱、发运;（四）滚动轴承的优缺点1）优点①摩擦系数小,摩擦阻力及起动力矩小,功率消耗小,机械效率高,负荷、转速和工作温度的适应范围较宽,工况条件的少量变化,对轴承性能的影响不大；②外形尺寸已标准化,具有互换性好,安装、拆卸和维修都很方便,润滑和维护保养容易,大多数类型的轴承能同时承受径向和轴向负荷；③轴向结构紧凑,使机器的轴向尺寸大为减少；④精度高,磨损小,寿命长,能在较长时间内保持轴的安装精度;⑤具有自动调心性能的轴承,当主轴有轻微挠曲或配合部件有些不同心时仍能正常工作；⑥适宜于专业化大批量生产,质量稳定、可靠,生产效率高;2缺点不宜承受强大的冲击和振动,运转时有振动和噪音,制造成本较高;二;滚动轴承的分类一滚动轴承按承受载荷的方向分类载荷的概念载荷分为径向载荷和轴向载荷；轴向载荷是指轴承载荷的作用方向平行于轴承的轴心线;径向载荷是指轴承载荷的作用方向垂直于轴承的轴心线;承受轴向载荷的能力随载荷的作用线与轴承径向平面之间的夹角的增大而增大;1．向心轴承包括：①向心球轴承：主要用于承受径向载荷,同时也可以承受不大的轴向载荷;②向心短圆柱或滚针轴承：主要用于承受径向载荷;③角接触向心轴承：能承受径向和轴向的联合载荷,一般以径向载荷为主;2．推力轴承包括：①推力轴承：仅用于承受轴向载荷;②角接触推力轴承：主要承受轴向载荷,也能承受不大的径向载荷;二滚动轴承按滚动体分类1．球轴承：深沟球轴承、调心球轴承、角接触球轴承、推力球轴承等; 2．滚子轴承：圆柱滚子轴承、滚针轴承、圆锥滚子轴承、调心滚子轴承、螺旋滚子;三滚动轴承按外径尺寸分类分为: ①微型轴承： D<26mm；②小型轴承： 26mm≤D<60mm;③中小型轴承： 60mm≤D<120mm; ④中大型轴承： 120mm≤D<200mm;⑤大型轴承： 200mm≤D<400mm; ⑥特大型轴承: 400mm≤D<2000mm;⑦重大型轴承: D≥2000mm;四滚动轴承类型代号新旧对照表三．滚动轴承代号的组成是用字母加数字来表示滚动轴承的结构、尺寸、公差等级、技术性能等特征的产品符号,由基本代号、前置代号、后置代号构成;一滚动轴承代号排列规则表2-1二滚动轴承基本代号表示的含义基本代号表示轴承类型、尺寸系列及内径代号;三尺寸系列代号的含义轴承尺寸系列代号由宽度系列代号和直径系列代号构成;1．直径系列指对应同一轴承内径的外径尺寸系列,也就是指相同内径的轴承有各种不同的外径,分别有：7、8、9、0、1、2、3、4、5等外径尺寸依次递增;2．宽度系列指对应同一轴承直径系列的宽度尺寸系列,也就是指直径系列相同的轴承有各种不同的宽度或高度,分别有8、0、1、2、3、4、5、6等宽度尺寸依次递增;四内径代号的含义轴承公称内径φ10—φ480mm内径代号的表示方法例：16205—ZN：6表示单列深沟球轴承；02表示尺寸系列为02系列；05表示内径尺寸为25mm；ZN表示外圈有止动槽一面带防尘盖的轴承;26203—2RS/Z2：6表示单列深沟球轴承；02表示尺寸系列为02系列；03表示内径尺寸为17mm；2RS表示两面带接触式橡胶密封圈；Z2表示振动加速度级值符合Z2组;五滚动轴承外部结构变动常见的代号及含义K：锥度1：12；N：轴承外圈有止动槽；—Z：轴承一面带防尘盖；—2RZ：轴承两面带非接触式橡胶密封圈；—ZN：轴承一面带防尘盖,另一面外圈有止动槽；—2Z：轴承两面带防尘盖；四．滚动轴承常用技术条件滚动轴承的技术条件是指轴承制造精度而言,主要包括各种公差等级的尺寸精度和旋转精度,以及其它技术要求．例如：硬度、游隙、旋转灵活性、振动和噪音、残磁、外观质量、标志和包装等;一轴承噪音等级的分组分Z1；Z2；Z3；Z4;噪音依次降低;二我公司生产轴承的精度等级轴承的精度按其基本尺寸精度和旋转精度分级;圆锥轴承有P0；P6X；P5；P4级轴承;其余各类轴承有P0；P6；P5；P4；P2级轴承;1．滚动轴承基本尺寸精度包括：内径、外径、宽度的制造精度;2．滚动轴承旋转精度包括：①成套轴承内圈和外圈的径向跳动Kia和Kea；②成套轴承内圈和外圈端面对滚道的跳动Sia和Sea；③内圈基准端面对内径的跳动Sd；④外表面母线对基准端面倾斜度的变动量S D;⑤推力轴承垫圈滚道对底面厚度的变动量Se；三滚动轴承游隙的分类分为径向游隙和轴向游隙1．径向游隙是指在无载荷时当轴承一个套圈固定,另一个套圈沿径向由一个极端位置到另一个极端位置的移动量;游隙是轴承工作的重要参数,它直接影响轴承的负荷分布、振动、噪音、摩擦、寿命、精度、刚性和运转精度;另一方面轴承的游隙因配合的种类、转速、温升的不同会发生变化;根据轴承所处的状态不同,游隙分为：原始游隙、安装游隙和工作游隙;一般三者是不相同的,选用时必须考虑到游隙的变化情况;1径向游隙的分组径向游隙分为C1；C2；C0；C3；C4；C5C0为基本组,在代号中可以不表示;2大游隙和小游隙适用哪些场合大游隙适用于轴承与轴和外壳采用过盈配合,轴承内圈与外圈温差较大,深沟球轴承需要受较大轴向载荷或需改善调心性能,要求提高极限转速以及降低摩擦力矩等场合;小游隙适合要求较高的旋转精度,严格控制轴或外壳的轴向位移以及需要减少振动和噪音等场合;2．轴向游隙略四新颁布滚动轴承公差符号及字母的含义答：V：表示变动量； m：表示平均； P：表示平面;s：表示单一; d：轴承公称内径; D：轴承公称外径；B：内圈公称宽度；C：外圈公称宽度; S：表示侧面;i：表示内圈； e：表示外圈； K：表示径向圆跳动;Δ：表示偏差; R：曲率半径; α：公称圆锥角;（五）轴承套圈形位公差符号及新旧术语对照表（六）滚动轴承钢的性能要求轴承内、外圈滚道和滚动体在很高的接触应力作用下进行相对滚动运动,滚动体和滚道之间还不可避免的存在着少量的滑动摩擦和滚动摩擦;滚动体、保持架、套圈挡边相互之间也存在着摩擦;因此,制造轴承套圈和滚动体的材料是轴承质量的基础;1．硬度及冲击韧性的概念1硬度是金属材料抵抗硬的物体压入其表面的能力;2冲击韧性是金属材料抵抗冲击载荷而不被破坏的能力;2．滚动轴承钢要求有较高的接触疲劳强度、有良好的耐磨性、有较高的弹性极限、有适宜的硬度、有一定的韧性、有良好的尺寸稳定性、有一定的防锈性能、有良好的加工工艺性能;3．我厂常用的轴承钢及性能我厂常用高碳铬轴承钢,牌号为GCr15和GCr15SiMn；高碳硌轴承钢是含铬~%的高碳合金钢,热处理后显微组织比较稳定,硬度高而均匀,耐磨性好,接触疲劳强度高,具有良好的尺寸稳定性和耐腐蚀性;经球化退火后,其切削加工性能良好,价格便宜;可以满足一般工作条件下运转轴承的使用要求;4．对轴承套圈和滚动体硬度的规定材料为GCr15；淬火后：套圈硬度：HRC61~65；滚动体：HRC62~66；七常用保持架的材料有黑色金属例如08和10优质碳素钢板等、有色金属如黄铜类、铜铝合金、铝合金等、非金属材料如酚醛胶布、尼龙等我公司调心球轴承和双列角接触轴承两个系列轴承全系列采用尼龙保持架其特点是重量轻、耐磨、强度好且有一定的自润滑性,对适当提高轴承转速、降低噪音、延长使用寿命均是比较有利的;并且耐温120℃~-40℃,不变形;在高速、高真空、低温和防磁情况下工作的轴承保持架用这些材料制造是很理想的;八轴承的润滑润滑脂按其主要成份分为：钙基、钙钠基、钠基、锂基、钡基等多种;我厂常用锂基润滑脂；其耐温性能及抗水性能均较好,寿命长,可适用于环境温度150℃左右并且潮湿的场合,但成本较高;严禁使用钙基脂代替锂基脂1．轴承润滑的作用①使相互接触的表面之间形成一层油膜,把两表面隔开,减少接触面的摩擦和磨损;②采用油润滑时,能带走轴承内部大部分摩擦热,起到良好的散热作用;③采用脂润滑时,可防止外部灰尘、异物进入轴承,起到一定的密封作用;④润滑剂具有一定的防锈的作用;⑤减少振动和噪音,延长轴承的使用寿命;2．轴承润滑的方法主要有脂润滑；油润滑；固体润滑;1油润滑的方式油浴润滑；滴油润滑；循环润滑；喷雾润滑；喷射润滑;2脂润滑的方式锂基脂；高温锂基脂；3．润滑油的粘度的选择粘度是润滑油的重要特性,随着工作温度的升高,润滑油的粘度将会降低,一般轴承转速较高时,选用较低粘度的润滑油；载荷较大应选用粘度较高的润滑油;4．轴承中润滑脂充填量的规定以充满轴承空间的1/2~1/3为宜,高速旋转时仅填充至1/3;低速且密封要求较严格的情况下可填满轴承空间; 五．轴承选型和安装时的注意事项一轴承安装的注意事项轴承是一种精密的机械零件,其套圈和滚动体均有较高的精度和表面粗糙度;若安装不正确及易造成轴承零件的变形和损坏,甚至使轴承不能正常运转;实践证明,轴承安装不当是轴承早期失效的主要原因之一;在轴承安装或拆卸过程中,要注意以下几个方面：1．确保轴承及其安装环境清洁,即使肉眼看不见的微小灰尘进入轴承内,也会增加轴承的磨损、振动和噪声;因此,装拆轴承的现场要清洁,轴承的清洗要干净;脂润滑的密封轴承不需要清洗2．装拆操作要认真仔细,不允许强力冲击,不允许用铁、铜锤直接敲击轴承,不允许通过滚动体传递安装力;应采用专用工具安装;允许加热轴承装轴;用油箱加热轴承时,在距箱底一定距离处应有一网栅,或者用吊钩吊着轴承;轴承不能放到箱底上,以防沉淀杂质进入轴承内或不均匀的加热;加热温度必须控制在100℃以下,以防止发生回火效应,使轴承的硬度降低;3．要使用合适的装拆工具,尽量用专用工具;极力避免使用布类和纤维之类的东西;避免微尘进入轴承内;4．轴承安装时要使轴和座孔的中心线重合;即同轴度要好;5．工作游隙和安装游隙轴承在实际运转条件下的游隙,称为工作游隙;在一般情况下,工作游隙总是大于安装游隙;特别是圆锥轴承、带锥孔的轴承、角接触轴承和推力轴承在安装时要注意调整好工作游隙;6．在安装过程中调心球轴承允许内、外圈轴线有一定的倾斜角度在普通载荷下,轴受载弯曲或加工不良及安装误差造成内、外圈倾斜角度最大允许值为3℃;深沟球轴承允许值为8′；7．安装后要确保轴承的工作环境和位置,清洁准确;8．安装后要确保轴承的润滑情况良好;二轴承选型的注意事项1．轴承的选择滚动轴承的选用直接关系到主机的工作性能,甚至影响主机的寿命;因此,在选用轴承时要根据各类轴承所具有的不同性能、精度、游隙以及机械的工作情况、负荷情况、转速要求等,选择适宜的轴承类型,仔细分析比较各类轴承的特性及性价比;通常选择轴承类型时应考虑如下因素：1分析掌握机械装置和轴承的使用条件;2明确对轴承的要求;3选择轴承的类型;4选择轴承的配置方式;5选择轴承的尺寸规格;6选择轴承的安装方法;2．滚动轴承配合中采用的基准制1）滚动轴承内圈与轴的配合采用基孔制；2）外圈与座孔的配合采用基轴制;3）一般采用较紧的过渡配合;3．轴承运转时所承受载荷的性质轴承运转时所承受载荷的性质分为：固定载荷局部载荷、旋转载荷循环载荷、摆动载荷、交变载荷、冲击载荷及振动载荷;4．对调心性的要求：外球面向心球轴承、调心球轴承和推力调心滚子轴承均具有较好的调心性能;5．对刚性的要求：所谓刚性是指轴承产生单位变形所需力的大小;当需要支撑刚度时,可选用圆柱滚子轴承或圆锥滚子轴承,因为这类轴承是线性接触,故弹性变形小,承载能力大;6．对轴承速度性能的要求：向心球轴承、角接触球轴承、圆柱滚子轴承等的极限转速均较高;7．游隙的选择和轴承的预紧1游隙是轴承是否正常工作的一个重要因素;选择适宜的轴承游隙,可以使负荷在滚动体之间分布合理,能限制轴或外壳的轴向和径向位移,从而保证轴的旋转精度;还能使轴承在要求的温度下正常工作,减少轴承工作时的振动和噪声,提高使用寿命;在选择轴承的游隙时,除应考虑轴承的工作条件如：负荷、转速、温度等和对轴承使用性能的要求如：摩擦力矩、振动和噪声、旋转精度等之外,还应考虑下列几点：A.轴承与轴和外壳的过盈配合导致游隙减小；B.轴承工作时内、外套圈的温度差导致游隙减小；C.轴和外壳的制造材料因膨胀系数不同导致游隙的减小或增大；2滚动轴承的预紧是指轴承装入轴承座和轴上后,使滚动体和内、外圈之间产生一定量的预变形,以保持内、外套圈和全部滚动体处于均匀压紧状态;在预紧状态下使用是滚动轴承的特点之一,其预紧的目的是：A.增加轴承的刚度;各类轴承通过预紧均可以增大支撑刚性;B.使旋转轴在轴向和径向正确定位,提高轴的旋转精度;C.减少轴承的振动和噪声;D.防止或减少滚动体的公转和自转打滑;8．其他要求在选择时还应综合考虑主轴对轴承轴向游动的要求,工作环境、尺寸精度的限制,安装拆卸是否方便,密封、摩擦力矩、振动、噪音等的特殊要求;9．单列深沟球轴承的性能特点结构简单,使用方便,摩擦损失小,极限转速高;但不耐冲击,不适宜承受重载荷,增大径向游隙具有一定角接触的性能,在轴向游隙范围内可限制轴和外壳两个方向的轴向位移;是我国产量最高,使用最普遍,价格最便宜的轴承;10．圆锥滚子轴承的性能特点负荷能力强,主要用来承受以径向载荷为主和一个方向的轴向载荷,可限制轴或外壳一个方向的轴向位移,因此可以作单向轴向定位;结构为分离型,可分别安装内圈和外圈,外圈可以互换,安装和拆卸比较方便,当游隙过小时,温升较高,当游隙过大时,振动加大,安装时不允许轴与外壳倾斜;11．推力球轴承的性能特点由一列钢球带保持架一个轴圈与轴紧配合和一个座圈组成;接触角α=90°,不能承受径向载荷,只能承受一个方向的轴向的载荷;负荷能力较大,允许极限转速较低;六．常见轴承的故障及失效情况各种机械装置均要求滚动轴承具有精度高、负荷力大、刚性好、摩擦力矩小及旋转平稳等性能,同时要求在使用期内能保持所需要的性能指标,低于使用要求而不能正常工作时,就称为轴承损坏或失效;轴承损坏前的使用期限就是广义的轴承的寿命;滚动轴承损坏或失效的形式有接触疲劳剥落；裂纹和断裂；塑性压痕；磨损烧伤；电流腐蚀；锈蚀；保持架损坏；精度降低；振动噪音大；摩擦力矩增大等;轴承损坏或失效的原因大多是由于安装使用不当造成的,例如：选型不合理、安装不正确、润滑不良、预紧不当、配合不当、尘埃和异物进入等等;但无论轴承设计的多么合理,使用条件多么合适,轴承也不可能永久的使用下去,终究会因为滚动表面的疲劳剥落而损坏;滚动轴承的寿命定义为：轴承中任意滚动体或滚道出现疲劳剥落前总的转速,或一定转速下的工作小时数;寿命的单位常用106转或小时表示;我们通常所说的寿命一般指的就是疲劳寿命;大量的试验表明：结构设计、材料和加工方法相同的一批轴承,在相同的条件下进行试验,其寿命数据有很大的离散性,最长寿命和最短寿命可能相差几十倍甚至上百倍,因而轴承的疲劳寿命是个随机的变量,寿命的离散性可以认为是由于材料内部组织和夹杂物分布的随机性、表面微观缺陷的随机性和试验条件不可避免的差异等随机因素造成的;评定滚动轴承寿命质量常用额定寿命和中值寿命这两个量;额定寿命：是指一批相同的轴承中,90%的轴承在疲劳破坏前能够达到或超过的寿命;中值寿命：是指一批相同的轴承中,50%的轴承在疲劳破坏前能够达到或超过的寿命;一滚动轴承破坏形式及产生的原因1．接触疲劳剥落：主要是安装使用不当造成的;如：安装误差滚动体受力、同轴度不好、轴承及环境不清洁、安装不到位产生偏移等、润滑不良、灰尘进入等;2．裂纹和断裂：安装不当或者受冲击负荷,轴承会发生微小的裂纹甚至断裂; 3．塑性压痕：受冲击力或载荷过大产生塑性变形过大,轴承工作表面上形成塑性变形凹坑,使摩擦和振动增大,运转不平稳,轴承无法正常工作;4．磨损及烧伤：轴承由于润滑不良、灰尘砂砾等异物进入、清洗不干净、润滑剂中的杂质以及工作表面锈蚀等因素,使轴承工作表面的磨损增加;当滚动表面局部摩擦和发热急剧增加,接触表面之间不能形成油膜,在干摩擦状态下就会发生烧伤;从而造成轴承的早期失效;5．电流腐蚀：当轴承内部有电流通过时,滚动体和滚道接触处很薄的油膜被击穿产生电火花,造成局部表面熔融的现象称为电蚀;6．锈蚀：产生锈蚀的因素较多,主要有酸、碱和水的溶液或气体侵入轴承时、空气中的水份凝结成水雾或水滴,附着在轴承上、润滑剂的添加剂中含有的硫磺或氯化物,在高温时分解或在水份侵入时,都会使轴承产生锈蚀;7．保持架损坏：主要原因是润滑不好滚动体和保持架之间磨损增加,继之可使保持架发生变形和断裂;二影响轴承噪音的常见原因①轴承内部清洁度；②滚动体的单体振动；③套圈滚道的粗糙度及圆度；④滚道或滚动体有伤；⑤刮盖等;实践证明,内圈、外圈、钢球三者对滚动轴承振动、噪音影响由强至弱的顺序为钢球、内圈、外圈;三残磁对轴承的影响残磁：轴承零件经退磁后残留的磁性;残磁对轴承的使用寿命有很大的影响,有了残磁的轴承,不仅不易洗净工作表面上的铁沫,工作中产生的铁沫也被吸附在轴承的工作表面上,加速了轴承的磨损;四滚动轴承的表面质量滚动轴承的表面质量指表面粗糙度和表面缺陷;1．表面粗糙度是指加工表面上具有的较小间距和峰谷所组成的微观几何形状特性,即表面微观的不平度;2．表面缺陷包括：裂纹、烧伤、打印质量、黑皮、磨伤、麻点、划伤、碰伤、锐角、毛刺和其他机械伤及材料缺陷等;五轴承的锈蚀及原因1．锈蚀是指金属表面与外界介质产生化学反应或由于电化学作用发生氧化而引起的破坏;轴承中常见的锈蚀有片状黄锈、蜂窝状孔锈、指纹锈、黄印锈、黑印锈及碰伤后产生的黑锈;2．轴承零件锈蚀的原因①潮湿的空气；②酸性物质；③腐蚀性碱、盐类；④尘埃和杂质；⑤不遵守防锈制度和防锈规程;七．轴承经销和使用过程中的常识一如何鉴别真假HRB轴承1．HRB民用产品三等分标志的内容：型号、HRB、CHINA；。
轴承章节知识整理一．滚动轴承1.轴承的功用：轴承是支承轴的零（部）件，并保持轴的正常工作位置和旋转精度。
2.轴承的分类按轴承工作摩擦性质，可分为滚动轴承和滑动轴承。
按轴承所受载荷方向不同，可分为径向轴承、止推轴承和径向止推轴承。
3.轴承的结构组成：内圈、外圈、保持架、滚动体保持架的作用：避免滚动体直接接触，减少发热和磨损；内圈：装在轴颈上，与轴一起转动；外圈：装在轴承座孔中，固定不动；滚动体：在两套圈之间滚动并传递载荷。
滚动体分为：球和滚子（圆柱形、圆锥形、滚针、鼓形等）4.轴承的选材：内圈、外圈、滚动体选用轴承铬钢GCr6、GCr9、GCr15 、GCr15SiMn ，硬度60~65 HRC；要求：具有较高的硬度、接触疲劳强度、耐磨性和冲击韧性。
加工工艺：磨削和抛光。
保持架：低碳钢冲压成形；铜、铝、工程塑料。
为适应某些特殊要求，有些滚动轴承还要附加其他特殊元件或采用特殊结构，如轴承无内圈或外圈、带有防尘密封结构或在外圈上加止动环等。
5.滚动轴承的优点：1）在一定条件下，摩擦阻力小，效率高。
2)灵敏，工作稳定，且不随速度变化。
3)轴颈直径相同条件下，滚动轴承宽度较小。
4)滑简便，易于维护、密封。
5）内部间隙小，回转精度高。
6）标准化专业生产，供应充足，互换性好。
滚动轴承的缺点：1）在轴颈直径相同条件下，滚动轴承径向尺寸大。
2 ）抗冲击能力较差。
3）.寿命较短。
4.）安装精度要求高，由于滚动轴承不能剖分，有时（如位于长轴中部时）安装困难。
5）高速时噪音大。
6.滚动轴承的分类按载荷方向分，可分为向心轴承、推力轴承和向心推力轴承。
按滚动体形状分球轴承和滚子轴承。
8. 滚动轴承的代号前置代号、基本代号、后置代号等部分组成，其中基本代号是滚动轴承代号的核心。
前置、后置代号是轴承在结构形状、尺寸、公差、技术要求等有改变时，在其基本代号左右添加的补充代号。
前置代号用字母表示；后置代号用字母（或加数字）表示。
滚动轴承的基本代号类型代号（数字或字母）、尺寸系列代号【径系列代号（数字）、宽度（高度）系列代号（数字）】和内径代号（数字）备注：内径为22、28、32及≥500mm的轴承，内径代号直接用内径毫米数表示，但标注时与尺寸系列代号之间要用“/”分开。
滚动轴承国家标准目录(61个)1GB/T 271-1997GB 271-87滚动轴承分类GB(十二)3滚动轴承圆锥滚子轴承外形尺寸方案GB(五)5滚动轴承向心轴承外形尺寸总方案GB(十三)7GB/T 275-1993GB 275-84滚动轴承与轴和外壳的配合GB(七)9GB/T 281-1994GB 281-84GB 282-87滚动轴承调心球轴承外形尺寸GB(九)11GB/T 285-1994GB 285-87滚动轴承双列圆柱滚子轴承外形尺寸GB(九)13GB/T 290-1998GB 290-89滚动轴承冲压外圈滚针轴承外形尺寸GB(十二)注：“备注〞栏内指明该标准所在的滚动轴承标准合订本。
如GB(十二)即为GB《滚动轴承(十二)》标准合订本，以下各表同。
15GB/T 294-1994GB 294-83滚动轴承三点和四点接触球轴承外形尺寸GB(九)17GB/T 297-1994GB 297-84(GB 298-64)滚动轴承圆锥滚子轴承外形尺寸GB(九)19GB/T 300-1995GB 300-87滚动轴承四列圆锥滚子轴承外形尺寸GB(十)21关节轴承分类GB(五)23关节轴承配合轴承标准应用手册25GB/T 305-1998GB 305-89滚动轴承外圈上的止动槽和止动环尺寸和公差GB(十二)27GB 307.2-84(GB 307-77)滚动轴承测量和检验的原则及方法GB(十)29部分代替滚动轴承推力球轴承公差GB(九)31GB/T 309-2000GB 309-1984滚动轴承滚针GB(十三)33GB/T4199-1984—滚动轴承公差定义轴承标准应用手册35GB/T4222-1991GB 4222-84杆端关节轴承外形尺寸和公差GB(七)37GB/T4661-1989GB 4661-84滚动轴承圆柱滚子轴承标准应用手册39GB/T4663-1994GB 4663-84滚动轴承推力圆柱滚子轴承外形尺寸GB(九)41GB/T GB 5801-86(JB 2582-79)滚动轴承径、中系列滚针GB(九)5801-1994轴承外形尺寸和公差43GB/T5868-1986—滚动轴承安装尺寸轴承标准应用手册45部分代替GB 6445-86滚动轴承滚轮滚针轴承外形尺寸GB(十一)47GB/T6643-1996ZBJ 11011-87(JB 3124-82)滚动轴承滚针和推力圆柱滚子组合轴承外形尺寸GB(十一)49GB/T7217-1987JB 1364-73凸缘外圈向心球轴承凸缘尺寸GB(四)51GB/T7811-1999GB 7811-87滚动轴承参数符号GB(十三)53GB/T8597-1988—滚动轴承包装GB(五)55GB/T9162-1990GB 9162-88)JB 2915-81JB 2916-81推力关节轴承外形尺寸轴承标准应用手册GB 9163-88)GB 304.5～304.8-81GB 3945-83向心关节轴承外形尺寸57GB/T9164-1990GB 9164-88)JB 2912-81JB 2913-81角接触关节轴承外形尺寸轴承标准应用手册59GB/T12764-1991—滚动轴承冲压外圈滚针轴承外形尺寸方案GB(七)61GB/T16940-1997ZB J11 006-87直线运动支承直线运动球轴承外形尺寸和公差GB(十二)注：1、“备注〞栏内指明该标准所在的滚动轴承标准合订本。
第十讲——常用机件的特殊表示法知识点8：滚动轴承的结构、分类及其代号1.滚动轴承的结构和种类支承回转轴的部件称为轴承，按照回转件与固定件之间摩擦的形式，轴承可分为滑动轴承和滚动轴承两种。
滑动轴承的摩擦阻力较大，应用较少，没有标准化；滚动轴承由于结构紧凑、摩擦阻力很小，所以在机械工程上被广泛采用。
滚动轴承的种类很多，几种常用的滚动轴承如下。
滚动轴承的结构主要由外圈、内圈、滚动体和隔离圈等部分组成。
滚动轴承与其他零件装配时，在一般情况下，其外圈装在机座的轴承孔内，固定不动，而内圈则装在回转轴上，与轴一起转动。
滚动轴承是标准件，其结构型式、特点、承载能力、类型和内径尺寸等均采用代号来表示。
轴承代号由基本代号、前置代号和后置代号构成，其中基本代号是表示滚动轴承的基础。
轴承代号的排列顺序是：前置代号、基本代号、后置代号。
(1)基本代号：由轴承类型代号、尺寸系列代号和内径代号构成，其排列顺序是：轴承类型代号、尺寸系列代号、内径代号a.轴承类型代号b.尺寸系列代号由轴承的宽(高)度系列代号和直径系列代号组合而成，用两位数字来表示。
它的主要作用是区别内径相同而宽度和外径不同的轴承。
c.内径代号表示轴承的公称内径，一般用两位阿拉伯数字表示，代号数字即为轴承内径。
公称内径为10-495mm的滚动轴承比较常用，但与尺寸系列之间用“/”分开，如深沟球轴承62/22 内径d=22mm；推力球轴承511/500 内径d=500mm。
(2)前置和后置代号是补充代号，是轴承在结构形状、尺寸、公差、技术要求等有改变时，在其基本代号左右添加的代号。
前置代号用字母表示，后置代号用字母(或加数字)表示。
滚动轴承的代号示例例1 深沟球轴承6206 规定标记为：轴承6206GB276-93，基本代号示例为：6 2 06表示轴承内径，d=6×5=30mm表示轴承尺寸系列代号，“0(2)”表示宽度系列代号0直径系列代号2，“0”常省略不标注表示轴承类型，“6”表示深沟球轴承例2 推力球轴承51107 规定标记为：轴承51107GB301-95，基本代号示例为：5 11 07表示轴承内径，d=7×5=35mm表示轴承尺寸系列代号，“11”表示高度系列代号1，直径系列代号1表示轴承类型，“5”表示推力球轴承知识点8：滚动轴承的结构、分类及其代号。
Bearing basicsSpecial Notes for iPad UsersFor iPad users, this course plays in the “Articulate mobile player app”, available free from the App store.The app offers a download option for offline learning, but please note that:1. An on-line connection is required to use the links on the “resources” tab2. If you wish to be able to print your course completion certificate then you need to be on-line when you take the end-of-course testTo continue, you can click the Home icon on the screen to return to the Welcome page of the course.WelcomeWelcome to the Basic introduction to rolling bearings course. This course will give you an introduction to SKF bearings and consists of three sections: Functions and parts,Applications and bearing types,and Designations.Module 1: Functions and partsWhy bearings?Bearings are an essential component of almost all machinery. They transmit loads between, support, guide and locate, machine elements that are required to move relative to each other with a minimum of friction, e.g.a rotating or oscillating shaft, pivot or wheel.Friction: Page 1Friction counteracts the movement between two surfaces. It is essential for the success of many operations, such as a car tyre gripping a road. In most machines however, friction is undesirable since it causes power loss, heat generation, wear and noise. SKF bearings help reduce friction.Friction: Page 2The earliest bearings were mostly made of wood and consisted of a shaft rotating in a hole in a housing, or a wheel rotating on a stationary shaft. Because the components were sliding over each other, friction was relatively high and wear rather rapid.This type of bearing is called a plain bearing and, made of modern materials, is still used in some applications today where speeds and loads are relatively low.Friction: Page 3The introduction of rolling elements between the shaft and the housing greatly reduces friction.Friction: Page 4Today, typical SKF rolling bearings combine maximum load capacity with minimum friction, using hardened steel or ceramic rolling elements, hardened steel inner and outer rings and a cage to guide and separate the rolling elements.Loads: Page 1A bearing can be under radial load, perpendicular to the shaft, or under axial load, acting in the direction along the shaft, or a combination of both radial and axial load, a combined load.Loads: Page 2Large bearings support heavier loads than small bearings can support, and roller bearings support heavier loads than ball bearings can support. Raceway contactThe basic difference between ball bearings and roller bearings is in the contacts between the rolling elements and the raceways. Balls have point contact; rollers have linear contact with relatively larger area.Bearing partsA typical rolling bearing consists of an inner ring, an outer ring and rolling elements contained by a cage. The most common type of rolling bearing is the deep groove ball bearing. These bearings can, as shown here, be supplied with integral seals to retain the lubricant and resist the ingress of contamination.Selection factorsThere are many factors, which will affect the choice of a bearing. These are: Available space, load, required service life, misalignment, speed, stiffness, axial displacement and clearance.Selection factors: SpaceSpace can be an important factor in bearing selection. Where radial space is limited a bearing with small diameter rolling elements, such as a needle roller bearing, may be needed.Selection factors: LoadWhen selecting a bearing, it is important to consider the direction of the load, and the amount of load the bearing will have to carry. A bearing can be under radial load, axial load, or a combination of both.Selection factors: Required service lifeThe life of a bearing can be expressed in terms of: the number of revolutions before failure, the number of operating hours before failure, or the distance covered (for cars and trucks). A bearing is considered to have failed when it shows the first sign of fatigue in a rolling element or raceway, or damage to other parts such as the cage or the seals. Service life is the real life that an individual bearing achieves in a particular application before it has to be replaced. It depends on a variety of influencing factors, including lubrication, the degree of contamination, misalignment, proper installation, and environmental conditions.Because service life cannot be calculated or predicted, bearings are selected using calculated rating life. SKF rating life L10m, a reference value calculated according to statistical methods, using modification factors for lubrication conditions and degree of contamination, and applying the same concept of a fatigue load limit as used in ISO 281, to estimate the life, with 90% reliability, that a sufficiently large population of apparently identical bearings might achieve when all are operating in an identical application.Selection factors: MisalignmentWhere a bearing is likely to be subject to angular misalignment, for example the shaft might bend due to operating loads, appropriate bearings need to be selected. Self-aligning bearings can accept a degree of operational misalignment and can also compensate for limited initial alignment errors in mounting.Selection factors: SpeedThe maximum speed that a bearing can be run in an application is limited by the maximum operating temperature for the materials used in its manufacture, or the lubricant. For high-speed applications minimum possible friction is important, so ball bearings are generally used. Selection factors: StiffnessElastic deformation occurs under load. Usually this deformation is very small and can be ignored. However, in some applications, stiffness is an important factor. Roller bearings have higher stiffness than ball bearings due to the larger area of the line contact.Selection factors: Axial displacementSome applications require bearings that allow the shaft to move axially relative to the bearing. This is called axial displacement. Most often, a shaft is supported by a locating bearing and a non-locating bearing. The locating bearing does not allow axial displacement and keeps the shaft in position. The non-locating bearing supports the shaft and allows displacement to prevent the bearings from being stressed. Cylindrical and CARB toroidalroller bearings can accommodate a limited degree of axial internal displacement.Selection factors: ClearanceThe amount of initial internal radial clearance required in a bearing depends mainly on the fits and temperature gradient between the inner and outer rings of the bearing in the particular application. Operational internal radial clearance is almost always less than initial internal clearance. SKF manufactures bearings with the following ranges of radial internal clearances:•C1 radial internal clearance less than C2•C2 radial internal clearance less than Normal•-- Normal radial internal clearance•C3 radial internal clearance greater than Normal•C4 radial internal clearance greater than C3SummaryIn this lesson, you have learnt about the functions of a bearing. These are: reducing friction, transmitting loads, locating and guiding moving parts. You have also been introduced to the different parts of a bearing: outer and inner rings, rolling elements, cage, and seals and their respective functionalities.Finally, you have also explored the different selection factors, which will affect your choice of bearing: available space, load, required service life, misalignment, speed, stiffness, axial displacement and clearance.Module 2: ApplicationsIntroductionIn this section you will be introduced to the most common bearing types offered by SKF.Electrical motors can be found almost anywhere there is mechanical movement.Motor: Page 2In this drawing you can see that the shaft is supported by two different bearings.Motor: Page 3Cylindrical roller bearings are simply bearings with cylindrical rollers. They can usually accommodate heavy radial loads and can operate at relatively high speeds.Motor: Page 4It is now time to choose the right side bearing.Motor: Page 5Deep groove ball bearings have deep uninterrupted raceways and close osculation between balls and raceways. This enables them to take axial loads in both directions.Pump: Page 1A pump is a device for lifting, transferring or moving fluids by suction or pressure from one position to another. This picture shows a medium-duty process pump, which is often used in refineries.Pump: Page 2In this drawing you can see that the shaft, which is running the impeller, is supported by one deep groove ball bearing to the right, and another bearing or bearings to the left.Single row angular contact ball bearings are widely used in medium and heavy-duty centrifugal pumps. They have raceways arranged at an angle to the bearing axis.Pump: Page 4Single row angular contact ball bearings can only take axial load in one direction. Therefore they are nearly always mounted as pairs in back to back or face to face arrangement at either end of a shaft, or as shown here, universally matchable bearings mounted immediately adjacent to each other.Fan: Page 1This is an industrial fan, in which SKF bearings are commonly used. Industrial fans can either be designed for light loads and high speeds, or for heavy loads and moderate speeds.Fan: Page2A fan is designed with two bearings along its shaft, placed between the fan and the motor. Both bearings carry radial loads and the bearing closest to the fan (on the left hand side here) also needs to be a locating bearing, keeping the shaft and the fan in a fixed position.Fan: Page 3Spherical roller bearings have two rows of rollers with a common raceway in the outer ring. The two inner ring raceways are inclined at an angle to the bearing axis.Fan: Page 4Returning to the fan application again, you now know which bearing is suitable as the locating bearing and here you have to make a guess concerning the non-locating bearing.CARB [ka:b] is a single row toroidal roller bearing with long, slightly crowned, rollers and concave raceways in both the inner and outer rings. Fan: Page 6The complete application looks like this with one spherical roller bearing and one CARB toroidal roller bearing.Separator: Page 1Alfa Laval, a Swedish company, has developed a range of machines specifically designed for rigorous oil processing duties. An example of this would be separators.Separator: Page 2The separation process creates imbalance due to the mud, which is distributed unevenly inside the separator and this makes the spindle bend. Separator: Page 3Self-aligning ball bearings have two rows of balls and a common concave sphered raceway in the outer ring. This makes the bearing insensitive to angular misalignments of the shaft relative to the housing. Self-aligning ball bearings accommodate high speeds due to the point contact between balls and raceways.Refiner: Page 1SKF bearings can be used in refiners in the production of mechanical pulp and other high-yield pulps.Refiner: Page 2In the process wood chips are ground at high mechanical pressure between a stationary disc and a rotating disc, which is powered by an electrical motor. The shaft between the motor and the grinding discs is supported by three bearings.Refiner: Page 3The high production capacity of the refiners is directly related to the demands on the bearing arrangement. The bearings have to provide high stability, operate at high speed, carry high thrust loads and handle deflections of the shaft.Refiner: Page 4The spherical roller thrust bearing incorporates a large number of asymmetrical, spherical rollers and has specially designed raceways. The load is transmitted from one raceway to the other at an angle to the bearing axis and the bearing can carry heavy axial load in one direction and some simultaneously applied radial load as well.Refiner: Page 5This is how the spherical roller thrust bearings are situated in the refiner application.Screw conveyor: Page 1Machines used in the agricultural industry often require bearings that can easily be changed and that can handle misalignments.Screw conveyor: Page 2This is a drawing of a screw conveyor attached to an agricultural machine. The bearings are the only contact between the screw conveyor and the machine.Screw conveyor: Page 3A Y-bearing unit consists of two parts: a housing and a bearing. The bearing is based on the deep groove ball bearing and can carry light radial and axial loads. It has a convex-sphered outside diameter, which allows the bearing to take up misalignment between the shaft and housing at the assembly stage. They are available with a wide range of highly effective,integral seals and a range of different methods for easy mounting to the shaft.Screw conveyor: Page 4This is what the Y-bearing unit looks like in the screw conveyor.Front wheel: Page 1SKF bearings are used in front wheels of commercial vehicles. These applications require bearings that can handle very heavy loads.Front wheel: Page 2This drawing shows how a truck front wheel arrangement is designed and where its bearings are situated. The bearings must carry a large part of the weight of the vehicle and the induced forces when driving, which means that they have to handle heavy loads in both radial and axial directions.Front wheel: Page 3Tapered roller bearings have tapered rollers running in tapered inner and outer ring raceways. This design makes them suitable for handling heavy combined loads.A tapered roller bearing can only carry axial loads in one direction and, for this reason, they are generally fitted in pairs.Front wheel: Page 4See how the tapered roller bearings are mounted in the front wheel of a commercial vehicle.SummaryIn this lesson, you have studied the most common SKF bearing types. Now click on each bearing picture to repeat the most important characteristics of each type. If you want to read more about SKF bearings, enter the SKF Interactive Engineering Catalogue on line at .Module 3: DesignationsIntroductionSKF bearing designations describe a bearing’s or component’s type, design, and variants. The designation can be found both on the box and on the bearing itself.Basic designations: Page 1A bearing designation for metric size bearings can either consist of a basic designation alone or a basic designation plus one or more supplementary designations, called prefixes and suffixes.The basic designation identifies the product type and size, while the supplementary designations identify design, special variants and bearing components.Basic designations: Page 2Each SKF bearing of standard metric design is given a basic designation, which normally consists of three, four or five figures.Basic designations: Page 3For example, the basic designation 22206 denotes a spherical roller bearing with the width series 2, diameter series 2 and a bore diameter of 30 mm.Supplementary designations: Page 1The supplementary designations consist of both prefixes and suffixes. Supplementary designations: Page 2Prefixes are used to identify component parts of a bearing and are usually followed by the designation of the complete bearing.Supplementary designations: Page 3Suffixes are used to identify designs, which differ in some way from the original design. The suffixes are divided into four main groups: Internal design, external design, cage design and variants, all of which are added to the basic designation in this order.End of course testNow it’s time to see what you learned.If you pass the test on-line then you’ll be able to print your course completion certificate.。
