§1-3滚动轴承1
滚动轴承-滚动轴承的结构及类型_
2.接触角
接触角是滚动轴承的一个主要参 数,轴承的受力分析和承载能力等与接 触角有关。表2列出各类轴承的公称接 触角。 滚动体套圈接触处的法线与轴承径 向平面(垂直于轴承轴心线的平面)之 间的夹角称为公称接触角。公称接触角 越大,轴承承受轴向载荷的能力也越大。
滚动轴承按其承受载荷的方向或公 称接触角的不同,可分为: (1) 径向轴承,主要用于承受径向载 荷,其公称接触角从0到45; (2) 推力轴承,主要用于承受轴向载 荷,其公称接触角从大于45到 90(表2)。
例2 试求N207轴承允许的最大径向载荷。 已 知 工 作 转 速 n=200r/min 、 工 作 温 度 t<1000C、载荷平稳、寿命Lh=10000h。 解:对向心轴承,由式(3)可得载荷为:
f T 10 F C f P 60 nLh
6
1/
由机械设计手册查得圆柱滚子轴 承N207的径向额定动载荷C=27200N; 因t<100C,由表8查得fT=1,因载荷 平稳,由表9查得fF=1,对滚子轴承取 =10/3。将以上有关数据代入上式, 得
推力轴承只能承受轴向载荷,因此其当 量动载荷为 P=A (7)
五、角接触球轴承和圆锥滚子轴承的轴 向载荷计算 角接触球轴承和圆锥滚子的结构特 点是在滚动体和滚道接触处存在着接触 角。当它承受径向载荷R时,作用在承 载区内第i个滚动体上的法向力Qi可分解 为径向分力Ri和轴向分力Si。各滚动体 上所受轴向分力的和即为轴承的内部轴 向力S(见图6a中的S1和S2)。轴承的内 部轴向力可以按表12计算。
10 F 27200 60 200 10 4
6
3 / 10
6469 N
滚动轴承 汽车变速箱用滚子轴承-最新国标
目次1 范围 (1)2 规范性引用文件 (1)3 术语和定义 (2)4 符号 (2)5 分类 (2)6 代号方法 (2)6.1 轴承的代号方法 (2)6.2 代号示例 (3)7 结构型式和外形尺寸 (3)7.1 圆柱滚子轴承 (3)7.2 圆锥滚子轴承 (8)8 技术要求 (9)8.1 材料及热处理 (9)8.2 公差 (10)8.3 倒角 (11)8.4 表面粗糙度 (11)8.5 游隙 (11)8.6 残磁 (12)8.7 清洁度 (12)8.8 振动 (12)8.9 旋转灵活性 (12)8.10 摩擦力矩 (12)8.11 外观质量 (13)8.12 寿命 (13)8.13 其他 (13)9 检测方法 (13)9.1 公差的测量 (13)9.2 滚子下垂量的检验 (13)9.3 倒角的检测 (14)9.4 表面粗糙度的测量 (14)9.5 游隙的测量 (14)9.6 残磁的测量 (15)9.7 清洁度的测试 (15)9.8 振动的测量 (15)9.9 摩擦力矩的测量 (15)9.10 旋转灵活性的检查 (15)9.11 外观质量的检查 (16)9.12 寿命试验 (16)10 检验规则 (16)10.1 出厂检验 (16)10.2 验收检验 (16)10.3 型式检验 (16)11 标志 (17)12 防锈包装 (17)附录A (资料性) 轴和轴承座与轴承配合处的技术条件 (18)滚动轴承 汽车变速箱用滚子轴承1 范围本文件规定了汽车变速箱用滚子轴承(以下简称轴承)的代号方法、结构型式、技术要求、检测方法、检验规则、标志和防锈包装。
本文件适用于汽车变速箱用轴承的制造。
2 规范性引用文件下列文件中的内容通过文中的规范性引用而构成本文件必不可少的条款。
其中,注日期的引用文件,仅该日期对应的版本适用于本文件;不注明日期的引用文件,其最新版本(包括所有的修改单)适用于本文件。
GB/T 272-2017 滚动轴承代号方法GB/T 274-2023 滚动轴承倒角尺寸最大值GB/T 283-2021 滚动轴承圆柱滚子轴承外形尺寸GB/T 297-2015 滚动轴承圆锥滚子轴承外形尺寸GB/T 307.1-2017 滚动轴承向心轴承产品几何技术规范(GPS)和公差值GB/T 307.2-2005 滚动轴承测量和检验的原则及方法GB/T 307.3-2017 滚动轴承通用技术规则GB/T 2828.1-2012 计数抽样检验程序第1部分:按接收质量限(AQL)检索的逐批检验抽样计划GB/T 4199-2003 滚动轴承公差定义GB/T 4604.1-2012 滚动轴承游隙第1部分:向心轴承的径向游隙GB/T 6930-2002 滚动轴承词汇GB/T 7811-2015 滚动轴承参数符号GB/T 8597-2013 滚动轴承防锈包装GB/T 24605-2009 滚动轴承产品标志GB/T 24607-2009 滚动轴承寿命与可靠性试验及评定GB/T 24610.3-2019 滚动轴承振动测量方法第3部分:具有圆柱孔和圆柱外表面的调心滚子轴承和圆锥滚子轴承GB/T 24610.4-2019 滚动轴承振动测量方法第4部分:具有圆柱孔和圆柱外表面的圆柱滚子轴承GB/T 25769-2010 滚动轴承径向游隙的测量方法GB/T 28268-2012 滚动轴承冲压保持架技术条件GB/T 32333-2015 滚动轴承振动(加速度)测量方法及技术条件GB/T 32562-2016 滚动轴承摩擦力矩测量方法GB/T 33624-2017 滚动轴承清洁度测量及评定方法GB/T 34891-2017 滚动轴承高碳铬轴承钢零件热处理技术条件JB/T 6641-2017 滚动轴承残磁及其评定方法JB/T 7048-2011 滚动轴承工程塑料保持架技术条件JB/T 7051-2006 滚动轴承零件表面粗糙度测量和评定方法JB/T 7363-2011 滚动轴承低碳钢轴承零件碳氮共渗热处理技术条件JB/T 8236-2023 滚动轴承双列和四列圆锥滚子轴承游隙及调整方法JB/T 8878-2011 滚动轴承冲压外圈滚针轴承技术条件JB/T 8881-2020 滚动轴承渗碳钢轴承零件渗碳热处理技术条件JB/T 8922-2011 滚动轴承圆柱滚子轴承振动(速度)技术条件JB/T 10236-2014 滚动轴承圆锥滚子轴承振动(速度)技术条件JB/T 10237-2014 滚动轴承圆锥滚子轴承振动(加速度)技术条件JB/T 10336-2017 滚动轴承补充技术条件3 术语和定义GB/T 4199-2003和GB/T 6930-2002界定的术语和定义适用于本文件。
滚动轴承
200
0.8
225
0.75
250
0.7
300
0.6
fT
滚动轴承的寿命计算
三、当量动载荷 当量动载荷:是由轴承实际所受载荷转换得到的与 基本额定动载荷 C 的确定条件及性质相同的假想载荷, 用 P表示。
当量动载荷 P f p ( XFR YFA )
式中:FR 、FA — 分别为轴承承受的径向载荷和轴向载荷;
3)被“压紧”轴承的 Fa 等于与除自身内部轴向力以外,其余各轴向力之和。
滚动轴承的寿命计算
五、同一支点成对安装同型号向心角接触轴承的计算
此种情况按双列轴承计算,双列轴承的基本额定动载荷 CΣ 和基本额定 静载荷 C0Σ 为根据单个轴承的 C 和 C0 计算: 角接触球轴承:
C 1 . 625 C C 0 2C 0
◆游隙代号: 游隙:指一个套圈相对于另一个套圈,沿径向或沿轴向,
从一个 极限位置到另一个极限位置的移动量。
游隙分为: /C1 、/C2、 0 、/C3 、/C4 、/C5 共六个组别。
游隙值:小 大
0组省略。
滚动轴承的代号
◆ 配置代号:
/DF:面对面安装(正装) /DB:背对背安装(反装) •举例: 6308: 深沟球轴承,尺寸系列03,内径d=40mm,
密 封 与 防 尘 结 构 代 号
保 持 架 及 其 材 料 代 号
特 殊 轴 承 材 料 代 号
公 差 等 级 代 号
游 隙 代 号
配 置 代 号
其 它 代 号
一、基本代号
◆ 内径代号:
代号 内径 d
00 10
01 12
02 15
03 17
机械基础(第四版)习题册答案
机械基础习题册参考答案绪论一、填空1.机器机构2.机构机构机器3.机构4.构件5.零件6.运动副7.面移动副转动副螺旋副点线二、选择题1.A2.A3.CA4.A5.A三、判断题1. ×2. √3. ×4. √5. ×6. ×7. √四、名词解释1.组成机器的各个相对运动的实体称为构件,构件可以是单一零件,也可以是由多个零件组成的一个刚性整体。
构件是机器中的运动单元。
2.机构是具有各种确定相对运动的各种实物的组合,它只符合机器的前两个特征,而不能实现机械能的转换。
3.两个构架之间直接接触又能产生一定相对运动的连接称为运动副。
4.两构件之间是面接触的运动副称为低副5.两构件之间是点或线接触的运动副称为高副五、简答题(1)都是人为的各种实物的组合。
(2)组成机器的各种实物间具有确定的相对运动。
(3)可代替或减轻人的劳动,完成有用的机械功或转换机械能。
六、实践题(答案仅供参考)1.(1)前叉车架辐条车轮圈等(2)传动机构:由链条、链轮、中轴、飞轮、脚蹬、曲柄等构成。
行动机构(车轮机构):由轮圈、辐条、轮胎、花鼓等构成。
安全机构:由刹车把、刹车线、刹车片等构成。
(3)自行车脚蹬和脚蹬轴之间自行车链和链轮之间(4)自行车车轮与地面之间自行车前后车轮轴中的滚动轴承滚动体与轮轴之间 2.(1)曲轴连杆活塞飞轮(2)圆周运动低副(3)摆动低副3.机器:a c e f机构:b d4.略第一章支承零部件§1—1 轴一、填空1.运动动力2.心轴转轴传动轴3.心轴4.转轴5.传动轴6.心轴7.直轴曲轴扰性钢丝轴8.碳素钢合金钢9.合金钢热处理10.轴颈轴身轴头轴肩(轴环)11.键销过盈配合紧定螺钉12.砂轮越程槽退刀槽同一母线位置上倒角二、选择题1.A2.B3.A三、判断题1.×2.×3.√四、名词解释1.轴颈轴上与轴承配合的部分叫做轴颈。
2.轴头轴上与传动零件(如带轮、齿轮、联轴器)配合的部分叫做轴头。
滚动轴承设计计算
(h)
通式
例6
6212轴承,承受径向力FR=5500N的平稳载荷,转速n=1250r/min,正常温度,试求寿命Lh 。
解: ∵纯径载 ∴P= FR=5500 N
C=47.8 KN
∵ 球轴承∴ ε= 3
查手册 :
∵ 正常温度平稳载荷 ∴ fT=1; fP=1
例7:轴径 d=50 mm, 纯径向载荷FR=6000N,载荷平稳,常温下工作,转速 n=1250 r/min, 预期寿命L h= 5000h.试选择此轴承.
二、滚动轴承的应力分析
三、滚动轴承的失效形式和计算准则
一、滚动轴承的载荷分析
§2 滚动轴承的受力分析、失效和计算准则
1)向心轴承:
FR0max
在径向力Fr的作用下
深沟球 60000
圆柱 滚子 N0000
半圈滚动体受载
各滚动体受力不均 受的最大力为 FR0max
Fr
一、滚动轴承的载荷分析—
载荷平稳∴fP=1;常温 ∴fT=1; P=X FR +YFA =4×0.4+3.55×1.7=7.64kN
∴30204不适用
再选30304查手册C=33kN>C /=31.5KN,可以吗? 不可以。∵此时e、x、Y、P值均发生了变化。
选轴承30304
查表:Cr =33 kN X=0.4 Y=2 e=0.3
二、轴承的寿命计算:
(r)
球轴承ε= 3
滚子轴承ε=10/ 3
且:载荷平稳;
常温 <1000C
可靠度90%;
对向心、向心推力轴承是纯径向力; 对推力轴承是纯轴向力。
C — 基本额定动载荷
P — 轴承所受动载荷
滚动轴承基本知识
滚动轴承基本知识一、滚动轴承的主要功能:在保证轴承有足够寿命条件下,用以支承旋转(或摆动)零件,传递负荷,减少运动副之间的摩擦,使之旋转(或摆动)灵活。
二、对轴承的基本要求:能够满足工作条件所要求的负荷、转速、工作精度、动态性能(噪声、振动)、环境温度和使用寿命。
三、滚动轴承的基本结构:由内圈、外圈、滚动体和保持架(俗称四大件)组成。
内圈与轴、外圈与轴承座孔装配在一起。
当内圈或外圈为旋转套圈时采用的是紧配合,不是旋转套圈时采用的是过渡配合。
滚动体(钢球、滚子或滚针)是滚动轴承的核心零件,当内外圈相对转动时,滚动体在内外圈的滚道之间滚动。
滚动体的形状、大小和数量直接影响轴承的负荷能力和使用性能。
保持架能够使滚动体均匀分布、引导滚动体旋转及改善轴承内部润滑性能。
四、滚动轴承的材料套圈和滚动体材料必须具有的特性:接触疲劳强度高;硬度高;纯洁度高;耐磨性好;组织稳定性好;机械加工性能好。
常用的轴承材料(套圈和滚动体):高碳鉻轴承钢:GCr15 、GCr15SiMn 等含鉻合金钢,热处理硬度一般为60 ~65HRC 。
是目前使用最广泛的轴承材料。
渗碳轴承钢:20CrMo 、20CrNiMo 等,渗碳热处理后表面硬度一般为59 ~64HRC ,心部硬度一般为30 ~45HRC 。
韧性好,能够承受较大冲击负荷。
保持架根据要求可以采用08 # 或10 # 钢板冲压保持架、HPb59-1 黄铜实体保持架、GRPA66 工程塑料保持架等。
五、滚动轴承的基本类型六、轴承的游隙滚动轴承的径向游隙系指一个套圈固定不动,而另一个套圈在垂直于轴承轴线方向,由一个极端位置移动到另一个极端位置的移动量。
轴承游隙的选择正确与否,对机械运转精度、轴承寿命、摩擦阻力、温升、振动与噪声等都有很大的影响。
如对向心轴承游隙的选择过小时,则会使承受负荷的滚动体个数增多,接触应力减小,运转较平稳,但是,摩擦阻力会增大,温升也会提高。
反之,则接触应力增大,振动大,而摩擦阻力减小,温升低。
滚动轴承
与滑动轴承相比,滚动轴承具有摩擦阻力小、起动灵敏、 效率高、润滑简便和易于互换等优点,所以获得广泛应 用。它的缺点是抗冲击能力较差,高速时出现噪声,工 作寿命也不及液体摩擦的滑动轴承。
滚动轴承通常按其承受载荷的方向(或接触角)和滚动体的形状 分类。 滚动体与外圈接触处的法线与垂直于轴承轴心线的平面之间的 夹角称为公称接触角,简称接触角。接触角是滚动轴承的一个 主要参数,轴承的受力分析和承载能力等都与接触角有关。接 触角越大,轴承承受轴向载荷的能力也越大。
轴承在很大的静载荷或冲击载荷作用下,会使轴承滚道和滚动体接触 处产生永久变形(滚道表面形成变形凹坑),从而使轴承在运转中产生 剧烈振动和噪声,以致轴承不能正常工作。
(2)永久变形
(3) 磨损
在滚动轴承内部,滚动体与套圈之间,以及保持架与滚 动体或套间之间均存在着滑动,从而引起轴承磨损。在 多尘或密封不好及润滑不良条件下,滚动轴承中易侵入
•按照承受载荷的方向或公称接触角的不同,滚动轴承可分为: 1)向心轴承、主要用于承受径向载荷,其公称接触角α 从0° 到45°;2)推力轴承,主要用于承受轴向载荷,其公称接触角 α 从大于45°到90°(表16-1)。
按照滚动体形状,可分为球轴承和滚子轴承。滚子 又分为圆柱滚子(图16-2a),圆锥滚子(图b)、球面滚子 (图c)和滚针(图a)等。
(2) 前置代号
轴承的前置代号表示成套轴承的分部件,用字母表示。如: L表示可分离轴承的可分离内圈或外圈;K表示轴承的滚动 体与保持架组件等。
(3) 后置代号
轴承的后置代号表示轴承的内部结构、密封、材料、公差、 游隙、配置及其它特性要求,用数字和字母表示。后置代 号共分8组,排列顺序见表16-6。
轴承的装配及调整
一般为6~12。
类型
固定式
——倾角固定,顶部预留平台
用来承受停 车后的载荷。
可倾式 ——倾角随载荷、转速自行调整,性能好
F
潘存云教授研制
F
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§1—3 滑动轴承的轴瓦结构
一、轴瓦的形式和构造
剖
整
分
体
式
式
单
双
金
金
属
属
§1—3 滑动轴承的轴瓦结构
整体轴套
二、摩擦状态
按表面润滑情况,摩擦可分为:干摩擦、边界 摩擦、流体摩擦和混合摩擦。
§1—1 概 述
1、干摩擦
两摩擦表面间无润滑剂,两固体表面直接接 触的摩擦。这种摩擦功率损失大,磨损严重。使 得轴承工作时温升强烈,严重时导致轴瓦烧毁。
因此在滑动轴承中不允许出现干摩擦。
干摩擦的摩擦阻力最大, f>0.3,磨损最严重,零件 的使用寿命最短
重要轴承采用这种摩擦。
f0.001~0.01
§1—1 概 述
4. 混合摩擦(也称为不完全液体摩擦)
混合摩擦介于边界摩擦与液体摩擦之间的一种 混合状态,在一般机器中最常见。
滑动轴承的摩擦特性曲线
图示的纵坐标表 示摩擦系数。横坐标 表示轴承特性数,其 中n是轴的转速;η是 润滑剂的动力粘度; p是轴承的压强。
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§1—2 径向滑动轴承的主要类型
一、整体式径向滑动轴承
§1—2 径向滑动轴承的主要类型
二、剖分式径向滑动轴承
剖分式径向滑动轴承装拆方便,轴瓦磨损后 可调整剖分面处的垫片来调整轴承间隙。
机械制造专业外文翻译--滚动轴承1
外文原文:Rolling Contact BearingsThe concern of a machine designer with ball and roller bearings is five fold as follows:(a) life in relation to load; (b) stiffness, i. e. deflections under load; (c) friction;(d) wear; (e) noise. For moderate loads and speeds the correct selection of a standard bearing on the basis of load rating will become important where loads are high, although this is usually of less magnitude than that of the shafts or other components associated with the bearing. Where speeds are high special cooling arrangements become necessary which may increase frictional drag. Wear is primarily associated with the introduction of contaminants, and sealing arrangements must be chosen with regard to the hostility of the environment.Because the high quality and low price of ball and roller bearings depends on quantity production, the task of the machine designer becomes one of selection rather than design. Rolling-contact bearings are generally made with steel which is through-hardened to about 900 HV, although in many mechanisms special races are not provided and the interacting surfaces are hardened to about 600 HV. It is not surprising that, owing to the high stresses involved, a predominant form of failure should be metal fatigue, and a good deal of work is based on accepted values of life and it is general practice in the bearing industry to define the load capacity of the bearing as that value below which 90 per cent of a batch will exceed a life of one million revolutions.Notwithstanding the fact that responsibility for the basic design of ball and roller bearings rests with the bearing manufacturer, the machine designer must form a correct appreciation of the duty to be performed by the bearing and be concerned not only with bearing selection but with the conditions for correct installation.The fit of the bearing races onto the shaft or onto the housings is of critical importance because of their combined effect on the internal clearance of the bearing as well as preserving the desired degree of interference fit. Inadequate interference can induce serious trouble from fretting corrosion. The inner race is frequently located axially by abutting against a shoulder. A radius at this point is essential for the avoidance of stress concentration and ball races are provided with a radius or chamfer to allow space for this.Where life is not the determining factor in design, it is usual to determine maximum loading by the amount to which a bearing will deflect under load. Thus the concept of “static load-carrying capacity” is understood to mean the load that can be applied to a bearing, which is either stationary or subject to slight swiveling motions, without impairing its running qualities for subsequent rotational motion. This has been determined by practical experience as the load which when applied to a bearing results in a total deformation of the rolling-element diameter. This would correspond to a permanent deformation of 0.0025 mm for a ball 25 mm in diameter.The successful functioning of many bearings depends upon providing them with adequate protection against their environment, and in some circumstances the environment must be protected from lubricants or products of deterioration of the bearing design. Moreover, seals which are applied to moving parts for any purpose are of interest to tribologists because they are components of bearing systems and can only be designed satisfactorily on the basis of the appropriate bearing theory.Notwithstanding their importance, the amount of research effort that has been devoted to the understanding of the behavior of seals has been small when compared with that devoted to other aspects of bearing technology.LathesLathes are widely used in industry to produce all kinds of machined parts. Some are general purpose machines, and others are used to perform highly specialized operations.Engine LathesEngine lathes, of course, are general-purpose machine used in production and maintenance shop all over the world. Sizes range from small bench models to huge heavy duty pieces of equipment. Many of the larger lathes come equipped with attachments not commonly found in the ordinary shop, such as automatic stops for the carriage.Tracer or Duplicating LathesThe tracer or duplicating lathe is designed to produce irregularly shaped parts automatically. The basic operation of this lathe is as fallows. A template of either a flat or three-dimensional shape is placed in a holder. A guide or pointer then moves alongthis shape and its movement controls that of the cutting tool. The duplication may include a square or tapered shoulder, grooves, tapers, and contours. Work such as motor shafts, spindles, pistons, rods, car axles, turbine shafts, and a variety of other objects can be turned using this type of lathe.Turret LathesWhen machining a complex workpiece on a general-purpose lathe, a great deal of time is spent changing and adjusting the several tools that are needed to complete the work. One of the first adaptations of the engine lathe which made it more suitable to mass production was the addition of multi-tool turret in place of the tailstock. Although most turrets have six stations, some have as many as eight.High-production turret lathes are very complicated machines with a wide variety of power accessories. The principal feature of all turret lathes, however, is that the tools can perform a consecutive serials of operations in proper sequence. Once the tools have been set and adjusted, little skill is required to run out duplicate parts.Automatic Screw MachinesScrew machines are similar in construction to turret lathes, except that their heads are designed to hold and feed long bars of stock. Otherwise, there is little different between them. Both are designed for multiple tooling, and both have adaptations for identical work. Originally, the turret lathe was designed as a chucking lathe for machining small castings, forgings, and irregularly shaped workpieces.The first screw machines were designed to feed bar stock and wire used in making small screw parts. Today, however, the turret lathe is frequently used with a collet attachment, and the automatic screw machine can be equipped with a chuck to hold castings.The single-spindle automatic screw machine, as its name implies, machines work on only one bar of stock at a time. A bar 16 to 20 feet long is fed through the headstock spindle and is held firmly by a collect. The machining operations are done by cutting tools mounted on the turret and on the cross slide. When the machine is in operation, the spindle and the stock are rotated at selected speeds for different operations. If required, rapid reversal of spindle direction is also possible.In the single-spindle automatic screw machine, a specific length of stock is automatically fed through the spindle to a machining area. At this point, the turret andcross slide move into position and automatically perform whatever operations are required. After the machined piece is cut off, stock is again fed into the machining area and the entire cycle is repeated.Multiple-spindle automatic screw machines have from four to eight spindles located around a spindle carrier. Long bars of stock, supported at the rear of the machine, pass through these hollow spindles and are gripped by collets. With the single spindle machine, the turret indexes around the spindle. When one tool on the turret is working, the others are not. With a multiple spindle machine, however, the spindle itself indexes. Thus the bars of stock are carried to the various end working and side working tools. Each tool operates in only one position, but all tools operate simultaneously. Therefore, four to eight workpieces can be machined at the same time.Vertical Turret LathesA vertical turret lathe is basically a turret lathe that has been stood on its headstock end. It is designed to perform a variety of turning operations. It consists of a turret, a revolving table, and a side head with a square turret for holding additional tools. Operations performed by any of the tools mounted on the turret or side head can be controlled through the use of stops.Machining CentersMany of today’s more sophisticated lathes are called machining centers since they are capable of performing, in addition to the normal turning operations, certain milling and drilling operations. Basically, a machining center can be thought of as being a combination turret lathe and milling machine. Additional features are sometimes included by manufacturers to increase the versatility of their machines.Numerical ControlOne of the most fundamental concepts in the area of advanced manufacturing technologies is numerical control (NC). Prior to the advent of NC, all machine tools were manually operated and controlled .Among the many limitations associated with manual control machine tools, perhaps none is more prominent than the limitation of operator skills. With manual control, the quality of the product is directly related to and limited to the skills of the operator. Numerical control represents the first majorstep away from human control of machine tools.Numerical control means the control of machine tools and other manufacturing systems through the use of prerecorded, written symbolic instructions. Rather than operating a machine tool, an NC technician writes a program that issues operational instructions to the machine tool. For a machine tool to be numerically controlled, it must be interfaced with a device for accepting and decoding the programmed instructions, known as a reader.Numerical control was developed to overcome the limitation of human operators, and it has done so. Numerical control machines are more accurate than manually operated machines, they can produce parts more uniformly, they are faster, and the long-run tooling costs are lower. The development of NC led to the development of several other innovations in manufacturing technology:1.Electrical discharge machining.ser cutting.3.Electron beam welding.Numerical control has also made machine tools more versatile than their manually operated predecessors. An NC machine tool can automatically produce a wide variety of parts, each involving an assortment of widely varied and complex machining processes. Numerical control has allowed manufacturers to undertake the production of products that would not have been feasible from an economic perspective using manually controlled machine tools and processes.Like so many advanced technologies, NC was born in the laboratories of the Massachusetts Institute of Technology. The concept of NC was developed in the early 1950s with funding provided by the U. S. Air force. In its earliest stages, NC machines were able to make straight cuts efficiently and effectively.However, curved paths were a problem because the machine tool had to be programmed to undertake a series of horizontal and vertical steps to produce a curve. The shorter is the straight lines making up the steps, the smoother is the curve. Each line segment in the steps had to be calculated.This problem led to the development in 1959 of the Automatically Programmed Tools (APT) language. This is a special programming language for NC that uses statements similar to English language to define the part geometry, describe the cutting tool configuration, and specify the necessary motions. The development of the APT language was a major step forward in the further development of NC technology.The original NC systems were vastly different from those used today. The machines had hardwired logic circuits. The instructional programs were written on punched paper, which was later to be replaced by magnetic plastic tape. A tape reader was used to interpret the instructions written on the tape for the machine. Together, all of this represented a giant step forward in the control of machine tools. However, there were a number of problems with NC at this point in its development.A major problem was the fragility of the punched paper tape medium. It was common for the paper tape containing the programmed instructions to break or tear during a machining process. This problem was exacerbated by the fact that each successive time a part was produced on a machine tool, the paper tape carrying the programmed instructions had to be rerun through the reader. If it was necessary to produce 100 copies of a given part, it was also necessary to run the paper tape through the reader 100 separate times. Fragile paper tapes simply could not withstand the rigors of a shop floor environment and this kind of repeated use.This led to the development of a special magnetic plastic tape. Whereas the paper tape carried the programmed instructions as a series of holes punched in the tape, the plastic tape carried the instructions as a series of holes punched in the tape, the plastic tape carried the instructions as a series of magnetic dots. The plastic tape was much stronger than the paper taps, which solved the problem of frequent tearing and breakage. However, it still left two other problems.The most important of these was that it was difficult or impossible to change the instructions entered on the tape. To make even the most minor adjustments in a program of instructions, it was necessary to interrupt machining operations and make a new tape .It was also still necessary to run the tape through the reader as many times as there were parts to be produced. Fortunately, computer technology became a reality and soon solved the problems of NC associated with punched paper and plastic tape.The development of a concept known as direct numerical control (DNC) solved the paper and plastic tape problems associated with numerical control by simply eliminating tape as the medium for carrying the programmed instructions. In direct numerical control .machine tools are tied, via a data transmission link, to a host computer. Programs for operating the machine tools are stored in the host computer and fed to the machine tool as needed via the data transmission linkage. Direct numerical control represented a major step forward over punched tape and plastic tape. However, it is subject to the same limitations as all technologies that depend on a hostcomputer. When the lost computer goes down, the machine tools also experience downtime. This problem led to the development of computer numerical control.The development of the microprocessor allowed for the development of programmable logic controllers (PLCs) and microcomputers. These two technologies allowed for the development of computer numerical control (CNC).With CNC, each machine tool has a PLC or a microcomputer that serves the same purpose. This allows programs to be input and stored at each individual machine tool. It also allows programs to be developed off-line and downloaded at the individual machine tool. CNC solved the problems associated with downtime of the host computer, but it introduced another known as data management. The same program might be loaded on ten different microcomputers with no communication among them. This problem is in the process of being solved by local area networks that connect microcomputers for better data manageme中文译文:滚动轴承对于球轴承和滚子轴承,一个机器设计人员应该考虑下面五个方面:(a)寿命与载荷的关系;(b)刚度,也就是在载荷作用下的变形;(c)摩擦;(d)磨损;(e)噪声。
习题册参考答案-《机械基础(第三版)习题册》-A07-9711
§1-3 滚动轴承 一、填空题 1.内圈 外圈 滚动体 保持架 2.球体 圆柱滚子 圆锥滚子 滚针 3.向心轴承 推力轴承 4.两端固定 一端固定、一端游动 5.压力机 软锤 6.拉拔器 7.润滑脂 润滑油 固体润滑剂 润滑脂 8.皮碗密封 毡圈密封 二、选择题 1.A 2.B 3.B 4.C 5.A 6.A 7.C 8.A 9.C 10.B 三、判断题 1.√ 2.× 3. √ 4. √ 5. × 6. × 7. × 8. × 9.× 四、解释下列滚动轴承代号的含义 1.
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§2-4 联轴器、离合器和制动器 一、填空题 1.刚性联轴器 挠性联轴器 2.啮合式 摩擦式 3.摩擦式 二、选择题 1.B 2.C 3.C 4.A 5.B 6.B 7.B 8.A 9.C 10.A 11.B 12.A 三、判断题 1.× 2.√ 3. √ 4. √ 5. √ 四、简答题 1. 联轴器可以用来连接轴与轴或轴与其他回转零件,以传递运动和转矩;离合器是 联轴器的一种特例。联轴器只能在机器停止运转后才能将两轴接合或分离;而离合器在机器 运转过程中可随时将两轴接合或分离,以便操纵机械系统运转、停车、变速和换向等。 2.工作可靠,接合平稳,分离迅速而彻底,动作准确,调节和维修方便,操作方便省 力,结构简单等。
一、填空
第二章 联接零部件 §2—1 键及连接
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1.轴和轴上零件之间的周向固定以传递扭矩 2.平键 半圆键 楔键 切向键 花键 3.圆头 方头 半圆头 4.键宽 键高 键长 5.导向 6.导向 7.普通楔键 钩头楔键 8.一个方向 两对 120°~130° 9.矩形花键 渐开线花键 10.小径定心 高 好 30° 齿侧 二、选择题 1.A 2.C 3.A 4.C 5.A 6.C 7.C 8.C 9.A 10.A 11.A 三、判断题 1.√ 2.√ 3.× 4.√ 5.× 6.× 四、简答题 1.普通平键上、下两面互相平行,两个侧面也互相平行。A型键在键槽中轴向固定好, 键与键槽配合较紧;B型键槽应力集中较小;C型键常用于轴端。 2.半圆键上表面为一平面,下表面为半圆形,两侧面互相平行,半圆键连接工作时靠键 两侧的工作面传递转矩。键在轴槽中能绕槽底圆弧曲率中心摆动,装配方便。键槽较深,对 轴的削弱较大。
滚动轴承概述
滚动轴承一、定义滚动轴承(rolling bearing)在承受载荷和彼此相对运动的零件间有滚动体作滚动运动的轴承。
它是将运转的轴与轴座之间的滑动摩擦变为滚动摩擦,从而减少摩擦损失的一种精密的机械元件。
二、结构和分类2.1.结构滚动轴承一般由内圈、外圈、滚动体和保持架四部分组成:1.外圈——装在轴承座孔内,一般不转动2.内圈——装在轴颈上,随轴转动3.滚动体——滚动轴承的核心元件4.保持架——将滚动体均匀隔开,避免摩擦目前,润滑剂也被认为是滚动轴承第五大件,它主要起润滑、冷却、清洗等作用。
如图2-1所示为滚动轴承的结构图。
图2-1 滚动轴承结构图2.2.分类2.2.1按滚动轴承结构类型分类2.2.1.1轴承按其所能承受的载荷方向或公称接触角的不同分为:1.向心轴承:主要用于承受径向载荷的滚动轴承,其公称接触角从0到45度。
按公称接触角不同又分为:径向接触轴承:公称接触角为0的向心轴承。
向心角接触轴承:公称接触角大于0到45的向心轴承。
2.推力轴承:主要用于承受轴向载荷的滚动轴承,其公称接触角大于45到90度。
按公称接触角不同又分为:轴向接触轴承:公称接触角为90度的推力轴承。
推力角接触轴承:公称接触角大5但小于90度的推力轴承。
2.2.1.2轴承按其滚动体的种类分为:1.球轴承:滚动体为球。
如图2-2所示。
图2-2 球轴承2.滚子轴承:滚动体为滚子。
如图2-3所示。
图2-3 滚子轴承滚子轴承按滚子种类,又分为:1.圆柱滚子轴承:滚动体是圆柱滚子的轴承,圆柱滚子的长度与直径之比小于或等于3。
2.滚针轴承:滚动体是滚针的轴承,滚针的长度与直径之比大于3,但直径小于或等于5mm。
3.圆锥滚子轴承:滚动体是圆锥滚子的轴承。
4.调心滚子轴承:滚动体是球面滚子的轴承。
2.2.1.3轴承按其工作时能否调心分为:1.调心轴承:滚道是球面形的,能适应两滚道轴心线间的角偏差及角运动的轴承。
2.非调心轴承(刚性轴承):能阻抗滚道间轴心线角偏移的轴承。
铁路货车轮轴简介(一)滚动轴承
一、铁路货车滚动轴承简介 2.2.2.5 铁道Ⅳ型脂装车使用
SKF197726
SKF197726型轴承使用的Ⅱ型A改性油脂的 颜色为棕色,其密封是接触式密封,摩擦以后导 致油脂变深,有的变为黑色。 通过论证,证明Ⅳ型脂完全能够代替Ⅱ型A 改性油脂。2006年10月1日起装用铁道车辆Ⅳ型 脂。
一、铁路货车滚动轴承简介
一铁路货车滚动轴承简介一铁路货车滚动轴承简介353130b353130b一铁路货车滚动轴承简介一铁路货车滚动轴承简介353130b353130b新的整体式低摩擦新的整体式低摩擦llll油封油封新的塑钢垫圈新的塑钢垫圈带有检查兜孔的新塑钢保持架带有检查兜孔的新塑钢保持架一铁路货车滚动轴承简介一铁路货车滚动轴承简介353130b353130b一铁路货车滚动轴承简介一铁路货车滚动轴承简介353130b353130b2252主要结构及特取消了密封座密封座的功能由内圈大挡边实现一铁路货车滚动轴承简介一铁路货车滚动轴承简介353130b353130b一铁路货车滚动轴承简介一铁路货车滚动轴承简介353130b353130b采用了ll型密封装置ll油封避免了微振磨蚀颗粒侵入轴承内具有良好稳定的密封性能提高了油脂及轴承使用寿命一铁路货车滚动轴承简介一铁路货车滚动轴承简介353130b353130b一铁路货车滚动轴承简介一铁路货车滚动轴承简介353130b353130b外油封牙口配合面外径凸台内油封配合面内油封增加1个特殊兜孔的设计方便轴承的一般检特殊兜孔识别标记数量
轴承型号
1. 既有铁路货车滚动轴承型号(19种)
● 无轴箱双列圆锥滚子轴承(15种): 25t轴重(9种):353130B(C353130)(主型) 、 CTBU150 (SKF ITALY V OR-7030 A) 、353130A 、 353130X2-2RZ 、 SKF 353130-2RS(SKF TBU150) 、TBU150(SKF ITALY V OR-7032)、 TAROL150/250TVP 808997 、 AP150 、 197730 (旧轮规) 。 21t轴重(5种):352226X2-2RZ(TN) (主型) 、 SKF197726 (主型) 、 197726TN 、 197726 (旧轮 规)、AP130 。 12t轴重(1种): 197720 (旧轮规) 。
滚动轴承的常用术语及定义
滚动轴承的常用术语及定义一.轴承:(一)滚动轴承总论1. 滚动轴承 rolling bearing在支承负荷和彼此相对运动的零件间作滚动运动的轴承,它包括有滚道的零件和带或不带隔离或引导件的滚动体组。
可用于承受径向、轴向或径向与轴向的联合负荷。
2. 单列轴承 single row bearing具有一列滚动体的滚动轴承。
3. 双列轴承 double row bearing具有两列滚动体的滚动轴承。
4. 多列轴承 multi-row bearing具有多于两列的滚动体,承受同一方向负荷的滚动轴承,最好是指出列数及轴承类型,例如:"四列向心圆柱滚子轴承"。
5. 满装滚动体轴承 full complement bearing无保持架的轴承,每列滚动体周向间的间隙总和小于滚动体的直径并尽可能小,以使轴承有良好的性能。
6. 角接触轴承 angular contact bearing公称接触角大于0°而小于90°的滚动轴承。
7. 调心轴承 self-aligning bearing一滚道是球面形的,能适应两滚道轴心线间的角偏差及角运动的轴承。
8. 可分离的轴承 separable bearing具有可分离部件的滚动轴承。
9. 不可分离轴承 non-separable bearing在最终装配后,轴承套圈均不能任意自由分离的滚动轴承。
注:对于不同方法分离零件的轴承,例如有双半套圈(02、01、08)的球轴承不另规定缩略术语。
10. 英制轴承 inch bearing原设计时外形尺寸及公差以英制单位表示的滚动轴承。
11. 开型轴承 open bearing无防尘盖及密封圈的滚动轴承。
12. 密封圈轴承 sealed bearing一面或两面装有密封圈的滚动轴承。
13. 防尘盖轴承 shielded bearing一面或两面装有防尘盖的滚动轴承。
14. 闭型轴承 capped bearing带有一个或两个密封圈,一个或两个防尘盖及一个密封圈和一个防尘盖的滚动轴承。
滚动轴承和滑动轴承的特点和区别
滚动轴承和滑动轴承的特点和区别标准化管理处编码[BBX968T-XBB8968-NNJ668-MM9N]滚动轴承和滑动轴承的特点和区别滑动轴承具有以下特点。
1、寿命长,适于高速。
2、能承受冲击和振动载荷。
3、运转精度高,工作平衡,无噪音。
4、结构简单,装拆方便。
5、承载能力大,可用于重载场合。
6、非液体摩擦滑动轴承,摩擦损失大;液体摩擦滑动轴承,摩擦损失与滚动轴承相差不多,但设计、制造润滑及维护要求较高。
滚动轴承的组成、类型及特点14.2.1 滚动轴承的组成滚动轴承一般由内圈、外圈、滚动体和保持架组成。
内圈装在轴颈上,外圈装在机座或零件的轴承孔内。
多数情况下,外圈不转动,内圈与轴一起转动。
(动画演示)当内外圈之间相对旋转时,滚动体沿着滚道滚动。
保持架使滚动体均匀分布在滚道上,并减少滚动体之间的碰撞和磨损。
运动动画拆装动画拆装拆装滚动轴承的基本结构常见的滚动体有6种形状,如图所示:滚动轴承的内外圈和滚动体应具有较高的硬度和接触疲劳强度、良好的耐磨性和冲击韧性。
一般用特殊轴承钢制造,常用材料有GCrl5、GCrl5SiMn、 GCr6、GCr9等,经热处理后硬度可达60-65HRC。
滚动轴承的工作表面必须经磨削抛光,以提高其接触疲劳强度。
保持架多用低碳钢板通过冲压成形方法制造,也可采用有色金属或塑料等材料。
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。
滚动轴承具有摩擦阻力小、启动灵敏、效率高、旋转精度高、润滑简便和装拆方便等优点,被广泛应用于各种机器和机构中。
滚动轴承为标准零部件,由轴承厂批量生产,设计者可以根据需要直接选用。
14.2.2 滚动轴承的类型及特点根据滚动体的形状,滚动轴承分为球轴承与滚子轴承。
按照滚动轴承所能承受的主要负荷方向,又可分为向心轴承(主要承受径向载荷)、推力轴承(承受轴向载荷)、向心推力轴承(能同时承受径向载荷和轴向载荷)。
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教案
文件编号:MEGJ/JW-JL-10(08)保存年限:5年
课程名称:机械基础教师:
章节内容§1-2滚动轴承(一)
授课班级14汽修②班
授课日期2015年月日(周)节课时 2 节目的要求了解滚动轴承的特点和主要结构
重点滚动轴承的类型难点滚动轴承的代号
仪器教具多媒体,轴承实物
作业练习习题册
审批意见
审批人: 20 年月日
教学内容和过程方法和指导
§1-2滚动轴承
滚动轴承已经标准化,并同轴承厂大批生产。
文件编号:MEGJ/JW-JL-10(08)保存年限:5年
教学内容和过程方法和指导
一、滚动轴承的构造
滚动轴承一般由外圈、
内圈、滚动体和保持架组
成。
1、内圈装配在轴颈上,
外圈安装在轴承座孔内。
多数情况下,内圈随轴旋
转,外圈不转动。
当内外圈之间相对旋
转时,滚动体沿着套圈上
的滚道滚动,使相对运动表面间为滚动摩擦。
2、保持架的作用是将滚动体均匀隔开,减少滚动体之间
的摩擦和磨损。
3、滚动体是滚动轴承形成滚动摩擦不可缺少的核心元件。
二、滚动轴承的类型和特性
GB/T272—93规定,滚动轴承的类型共有11种,表1—5
列出了滚动轴承的类型、特性及应用。
三、滚动轴承的代号
1.滚动轴承的代号
滚动轴承的类型很多,而各类轴承又有不同的结构,尺寸、
精度和技术要求等,为了便于组织生产和使用,GB/T 273—
93规定用字母加数字来表示轴承代号。
轴承代号由基本代号,前置代号和后置代号构成,其排列
如下:
前置代号后置代号基本代号
文件编号:MEGJ/JW-JL-10(08)保存年限:5年
教学内容和过程方法和指导 1.前置、后置代号
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。
2.基本代号
基本代号表示轴承的基本类型、结构和尺寸,是轴承代号
的基础,基本代号由类型代号、尺寸系列代号、内径代号构成,
并按此顺序排列。
类型代号用阿拉伯数字或大写拉丁字母表
示,尺寸系列代号和内径代号用数字表示。
⑴类型代号(见表1—5)
⑵尺寸系列代号
尺寸系列代号由轴承的宽(高)度系列代号和直径系列代
号组成。
向心轴承和推力轴承尺寸系列代号如表1—8所列。
⑶内径代号
表示轴承公称内径的内径代号如表1—9所列。
表1—9滚动轴承内径代号
轴承公称内径(mm)内径代号示例
10到17 10 00
深沟球轴承6200
d=10mm
12 01
15 02
17 03
20到480 (22、28、32除外)公称内径除以5的商数,商数为个
位数,需在商数左边加“0”,如
08
调心滚子轴承
23208
d=40mm
文件编号:MEGJ/JW-JL-10(08)保存年限:5年
教学内容和过程方法和指导 3.滚动轴承代号示例
1.滚动轴承代号实例
6 2 08
3 02 12 /P5 3 游隙为0组(省略)
公差等级为0级(省略)
内径d=40mm
尺寸系列代号(0)2,其中宽度系列为0(省略),直径系列为2
轴承类型为深沟球轴承
组合代号
游隙为3组
公差等级为5级(省略)
尺寸系列代号02,其中宽度系列为0,直径系列为2
内径d=60mm
轴承类型为圆锥滚子轴承
组合代号。