拧紧基础知识讲解-修改.ppt

1、美国英格索兰公司拧紧基础知识,拧紧机资料之一,工具形式及选择,POSITIVES正版的 High power to weight ratio高的功率重量比 Fast速度快 No Reaction反作用力小 Non Technical Maintenance不需要专门的维护 Compact紧凑 Inexpensive物美价廉,NEGATIVES盗版的 Little or No control半受控或不受控 Noisy有噪音 High Vibration高振动,冲击扳手,冲击扳手结构,双锤式,大型锤,滚珠凸轮机构,NEGATIVES消极,Torque Readout Run down speed

2、Two Hand Operation (angle wrenches),POSITIVES积极,Good Repeatability Inexpensive Low Overshoot,离合器型气动工具,价格适宜,低过冲,可重复性好,运行速度下降,双手操作,自己读力矩,Once pre set torque is delivered to the joint, Clutch spring gets compressed triggering the mechanism to shut off air supply to the motor, providing excellent repeat

3、ability.一旦预先设定的扭矩传递到结合处，离合器弹簧压缩，触发空气供应切断机制运行 ，并能重复性工作，且效果优良。,离合器自动断气型扳手,扭矩,推杆,马达末端,离合器弹簧,离合器调节螺母,螺丝起子,POSITIVES Accurate Low Noise Clean Closed - Loop Feedback Ergonomic Low Running Cost Can be interfaced with PLCs and BCRs,NEGATIVES High Initial Investment Torque Reaction Two hand operation (angle

4、tools),电动拧紧机,精确,噪音低,清洁,闭环反馈,人体工程学,运行成本低,可以与控制系统和BCRs连接,初始投资高,扭矩反作用,两手操作,拧紧机控制柜,拧紧工具选择,Operator Ergonomics (Reaction, Tool Weight, Arm Position, Frequency),Cycle Rate,Fastener and Drive Type,Access to Fastener (Size and Space Constraints),Joint Criticality,Data Collection,Torque Level,Budget,Power So

5、urce,Maintainability,Tightening Strategy,拧紧策略,可维修性,动力源,数据采集,结合处的危险程度,预算,紧固件通道,扭矩等级,循环速率,紧固件和驱动形式,人机工程学的应用（反作用力，工具重量，力臂位置，频率）,拧紧工具选择综述,Reliable bolted joints are dependent on many factors: Fastener quality and type Consistency of joint materials Assembly tool used Assembly method or strategy Operator

6、 Influence Frictional Scatter Maintenance of bolt clamp load Tool and assembly method selection should occur early in the design process to be most effective,螺栓连接的可靠性影响因素很多：,紧固件质量和类型,联合材料的一致性,所用的工具,安装方法或策略,操作人员的影响,摩擦的传递,螺栓夹紧力的保持,工具和装配方法的选择应在设计过程中及早进行，这样才最有效,扭矩测量术语,动态扭矩 - Peak Torque Measured During

7、the Installation of a Fastener Using a Power Tool- The Preferred and Most Accurate Measurement For Assembly Statistical process Control 峰顶扭矩测量应用在用扭力工具进行的紧固件安装中-这是统计过程控制最恰当最精确的测量方法。,静态扭矩 - Torque Value That Exist Without Producing Rotation in a Fastener在紧固件之间不发生相对旋转的扭矩值 - Used Only as an Indication o

8、f a Minimum Torque 只作为扭矩最小值的象征,残留扭矩 - Torque Measured After Fastener is Installed by Rotating The Fastener in Tightening Direction 在紧固件拧紧后进行扭矩测量 - Can Have Significant Measurement Error depending on equipment used to Audit Torque 由于扭矩测量设备的不同而出现明显的测量误差,扭矩测量,“标记法 Back-to-the-Mark” 准确度: 高 方便性/速度: 低 Mar

9、k then loosen Bolt. Tighten Back to Original Position 标记后柠松螺栓，再拧紧回初始位置。 Truly Checks Dynamic Tightening Torque 切切实实的检查动态拧紧扭矩 Works Only in Tapped Holes这种方法只适用于螺纹孔 Time Consuming耗费时间,扭矩测量,“Off-torque” 松动扭矩 准确度: 低 方便性/速度: 中 Measure Peak Loosening Torque测量松动扭矩的峰值 Measurement of Off-Torque Does Not Rela

10、te Accurately to Tightening Torque 松动扭矩与拧紧扭矩没有明确的联系,扭矩测量,定扭矩扳手 准确度: 低 方便性/速度: 高 Apply Torque Until Wrench Clicks at Set Torque扳手发出响声时所施加的扭矩即为设定扭矩 Not a Real Audit Method - Basically a Torque Re-Application Method不是一种真正的检测方法,基本上是一种扭矩再应用检测 Only Gives Assurance That Inspected Fastener Has Been Tightene

11、d只能确定检测的紧固件已经被拧紧,扭矩测量,测扭矩扳手 准确度: 低 方便性/速度: 中 Apply Torque Until Operator Senses Movement操作人员能够感应到移动之前的扭矩为适合扭矩 Read Peak Torque on Tool Indicator从指示器上读出峰值扭矩 Subject to Operators Skill and Joint Conditions收到操作者技能水平和连接条件的限制,扭矩测量,扭矩/角度 扳手带外部记录仪器 准确度: 较高 方便性/速度: 低 Capable of Measuring Dynamic Torque能够测量动

12、态扭矩 Equipment Is Bulky and Difficult to Use设备庞大很难用,扭矩测量,扭矩/角度 力矩扳手带有动态扭矩监测算法 准确度:高 方便性/速度: 高 Truly Checks Dynamic Torque After the Fastener Has Been Rotated a Small Amount 小幅度旋转紧固件之后能够真实地检测出动态扭矩,动态扭矩,Peak Static Torque静态扭矩峰值,Angle, q,Residual Torque Measured Dynamically残余扭矩的动态测量,Torque, T,“Snug”Torq

13、ue“事宜扭矩,工件连接基础知识,Hard Joint - 30 or less - high torque rate 硬连接30或更小高转矩率,Soft Joint - 720 or more - low torque rate 软连接720或更大-低扭矩率,连接形式,硬连接 30 or less rotation between snug and final torque (27 between 10% and 100% torque) 介于适宜扭矩与最后扭矩30度或小于30度的旋转 (0.27的公差)。,软连接 720 rotation between snug and final to

14、rque (650 between 10% and 100% torque) 介于适宜扭矩与最后扭矩做720度的旋转 (6.5的公差)。,JOINT RATES AS DEFINED BY ISO 5393连接率的定义由国际标准化组织5393界定,Joint rate highly effects the final clamp load achieved by a given torque连接率对最后给定的夹负载力矩有很大的影响力,TORQUE扭矩,TL,TH,TC,SNUG,27,As,30,A1,TL,TH,TC,SNUG适宜, 720,A0,As,连接形式,连接形式,PREVAILIN

15、G TORQUE Notable Torque Before Fastener Begins to Seat紧固件在开始设定位置前应予以重视 Can be Hard or Soft或是硬链接或只是软连接 Examples例如 -Thread Forming线程的形成-Thread Cutting 螺纹切削 -Self Locking 自锁功能-Damaged Threads-Damaged 螺纹破损,Prevailing Torque现行扭矩,SNUG,TL,TH,TC,拧紧基础知识,扭矩和转角,力臂 (Feet, Meters) 英尺、米,力 (Newtons, Pounds) 牛顿, 英镑

16、,扭矩 = 力 x 力臂,角度,90,135,拧紧基础,Tightening Threaded Fasteners is Basically an Energy Transfer Process 螺纹紧固件紧固过程主要是是能量转移的过程 Area Under Torque-Angle Curve is Proportional to the Energy Required to Tighten the Fastener 扭矩角度曲线以下的面积与紧固件紧固所需的能量成正比。 T = K d F T = Torque扭矩 d = Nominal Diameter名义直径 F = Force力 K

17、= Friction Factor 摩擦系数,角度, q,扭矩, T,扭矩消耗到哪里去了?,螺纹摩擦力,夹紧力,螺栓头摩擦力,扭矩,螺栓头摩擦力 55% 螺纹摩擦力- 35% 夹紧力 - 10%,拧紧曲线,拧紧曲线,扭矩控制拧紧过程,拧紧方法,The variation in clamp loads is controlled by friction scatter. Using a very accurate wrench will not help preload scatter. However, a very inaccurate wrench will have a detrimen

18、tal impact on preload scatter.夹紧力的变动收到摩擦散射的控制。使用非常精确的扳手不能缓解预紧力的散失。但是，非常不准确的扳手会对预紧力的散失产生不利影响。,扭矩控制拧紧,拧紧方法,扭矩控制拧紧,拧紧方法,Applied Torque Is Controlled Directly or Indirectly施加的扭矩是直接或间接地受控的 Target Torque Is Usually 50% to 85% of Yield Torque目标扭矩通常是屈服扭矩50%-85% Used in Elastic Range of Fastener在紧固件的弹性范围内使用

19、90% Of Applied Torque Is Used to Overcome Friction 施加扭矩的90%是用来克服摩擦力的 Also known as: Torque, Straight Torque也称为：扭矩、直接扭矩 Preload Accuracy 25%预紧力精确度25%,Step 1: Apply a Torque to Consolidate the JointComponents (Snug Torque) 第一步：施加扭矩来巩固部件的连接 Step 2: Turn the Fastener Through a Pre-determined Angle第二步:旋转

20、紧固件至预先设定的角度 Originally Developed for Beyond Yield Tightening, Now Also Used in the Elastic Range 最初是为了超出屈服区的拧紧,现在也用在弹性区内 Requires Application Testing to Establish Snug Torque and Angle Parameters 需要通过试验建立适宜的转矩和角参数 Also known as: Turn of the Nut, Torque-Angle 也称为:螺母旋转法，扭矩-角度法 Preload Accuracy 15%预紧力精

21、确度15%,角度控制,拧紧方法,角度控制,角度控制,Scatter in Preload is Caused Mainly by The Scatter in Friction During the Torque Tightening (Snug Torque) Portion of the Tightening Procedure预紧力的散失主要是由拧紧过程中摩擦力的散失引起的 During the Angle Tightening Portion There is no Scatter in Preload Due to Friction, Only the Scatter in Appl

22、ied Angle Turned在角度拧紧的部分，没有由摩擦力引起的预紧力散失，只有转角的散射。,角度控制,角度说明: Snug torque has a tolerance which can increase the initial clamp load scatter.初始扭矩的公差能增加预紧力的散失 A low snug torque should be used whenever possible. When a high snug torque is used, the effect of constant preload v. angle is lost.条件允许时应尽量选用低的

23、初始扭矩。而当使用一个高的初始扭矩时,预紧力与转角的恒定关系将不再有效。 A low snug torque will also reduce the effects of torque scatter before the angle is counted. 低的初始扭矩也会减小转角施加前的扭矩散失。 When tightening in the plastic range of a fastener, variation in yield strength is also a factor.在紧固件塑性区内工作时，屈服强度的变化也是一个影响因素。,屈服点控制,Torque and Angl

24、e Are Monitored During Tightening拧紧时需要监控扭矩和角度 The Maximum Gradient is Stored & the Yield Point Identified When the Gradient Falls to a Fraction of the Maximum当梯度下降到梯度最大值的一小部分时，最大梯度和屈服点同时被记录下来。 Utilizes Maximum Load Potential of the Fastener利用紧固件的最大承载潜力 Largely Uninfluenced by Friction在很大程度上排除了摩擦的影响

25、Allows Torque Angle Inspection of Every Tightening允许对所有的紧固实施扭矩转角的监控 Bolts Can Be Reused螺栓可以重复利用 Also known as: Torque to Yield扭矩屈服点 Preload Accuracy 8%,拧紧方法,屈服点控制,屈服点控制,Reduced Variation in Preload After Tightening:紧缩之后减少预负荷中的变形,Preload Scatter is More Dependent on Strength Variation Than Friction V

26、ariation 比起摩擦， 预紧力分散更依赖于强度变化 Bolt Strength is More Controllable Than Friction 螺栓强度比起摩擦力可控性更强。,PRELOAD, N,预负荷N,Thread线程,Grade,Size,Range,8.8,10.9,12.9,8.8,10.9,12.9,M4 x 0.7,Minimum,4,400,6,200,7,300,3.1,4.4,5.3,Maximum,5,600,7,600,8,800,4.3,6,7.2,M5 x 0.8,Minimum,7,200,10,000,12,200,6.4,9,11,Maximum

27、,9,200,12,400,14,600,8.7,12,15,M6 x 1.0,Minimum,10,200,14,200,16,100,11,14,18,Maximum,13,000,17,600,20,500,15,20,24,M8 x 1.25,Minimum,18,600,26,200,31,400,25,37,44,Maximum,23,800,32,200,37,800,36,51,60,M10 x 1.5,Minimum,29,800,41,600,50,000,52,73,88,Maximum,38,000,51,200,60,000,71,99,119,M12 x 1.75,

28、Minimum,43,400,60,700,72,900,92,128,156,Maximum,54,400,74,900,87,700,127,173,207,M14 x 2.0,Minimum,59,400,83,300,100,000,144,205,244,Maximum,75,600,102,000,120,000,200,280,335,M16 x 2.0,Minimum,82,500,115,000,138,000,228,322,383,Maximum,105,000,141,000,166,000,310,450,520,M18 x 2.5,Minimum,99,200,13

29、9,000,167,000,305,430,510,Maximum,127,000,171,000,201,000,420,595,710,Grade,夹紧力和理想扭矩,EXPECTED TORQUE, Nm预期的扭矩,海里,Clamp Load Scatter夹负荷分散,最小夹紧力,工具和螺栓选择,屈服点控制,Joint May Not Be Critical Enough to Warrant its Cost 与所花的费用相比，接合不够重要 Should Not Use When:以下情况不能使用： Bolt Yield Strength Joint Compressive Streng

30、th螺栓屈服强度大于联合抗压强度时 Bolt Yields Somewhere Other Than Threads螺栓除螺纹以外的地方发生了屈服 Head Shears螺栓头掉了 Nut Strips螺母的螺纹剥离 Applications Where Frequent Disassembly is Required频繁拆卸的场所 Joints With Unpredictable Stiffness Qualities连接的强度不可预知,If Yield is the Most Accurate, Why Not Always Use it? 如果屈服点控制是最准确的, 为什么不常用呢?,

31、拧紧错误,拧紧错误,FOUR MAJOR ERRORS DURING BOLT TIGHTENING : 螺栓紧固中的四大错：,Human errors 人为操作错误 Tightening method errors 紧固方法不当 Improper tool errors 工具不适宜 Joint parts errors 连接部位错误,Forgot to tighten忘记拧紧 Improper tools used使用了不恰当的工具 Wrong specifications规格错误 Wrong tightening procedure紧固方法错误 Wrong selection of too

32、ls工具的选取不当 Inaccuracy 不精确 Mechanical failure 机械故障 Out of parts tolerance超出了部件的承受力 Bad material材料不好 Insufficient lubrication润滑不充分,拧紧错误,CLASSIFICATION & CAUSE FOR LOOSENING OF BOLTS 螺栓松动分类及原因,拧紧错误,CHARACTERISTICS DIAGRAM OF DEFECTIVE JOINT缺陷连接特征图,拧紧错误,Tightening faults can be caused by the joint, the t

33、ool or the operator拧紧错误可由紧固件、工具或操作人员引起 These faults typically show up as major deviations from normal这些缺点通常显示为相对正常的偏离 The detection of tightening faults is best done by uncovering deviations from normal angle紧固故障的检测最好不要覆盖正常角度的偏离 Modern DC controllers have the capability to monitor or control angle t

34、o flag these process errors现代的直流控制器能够监视和控制的角度，平复进程中遇到的各种错误,装配过程中,拧紧错误,由下列方法判断:,错误种类,扭矩控制,Bolt too Soft,(Low or high friction conditions)摩擦过大或过小,NO,YES,YES,Bolt too Soft,(Normal Friction)摩擦适中,NO,Usually NO,YES,Bolt too Hard螺栓过硬,NO,NO,YES,Thread Fault,(Friction High)摩擦过大,NO,YES,YES,Coating/ Lube Fault

35、,(Friction extremely Low)摩擦微乎其微,NO,YES,YES,拧紧错误,Angle, q,Torque, T,Blind Hole Too Short孔的深度欠缺,Effect on Torque/Angle End of Cycle Data:,Torque,Angle,Tightening Cycles,Torque High Limit,Torque Low Limit,Angle High Limit,Angle Low Limit,拧紧错误,Angle, q,Torque, T,Incomplete Operation (tool shut off early

36、)没有完全操作,Expected,Effect on Torque/Angle End of Cycle Data:,Torque,Angle,Tightening Cycles,Torque High Limit,Torque Low Limit,Angle High Limit,Angle Low Limit,拧紧错误,Angle, q,Torque, T,Misaligned Parts忽略了角度,Effect on Torque/Angle End of Cycle Data:,Torque,Angle,Tightening Cycles,Torque High Limit,Torqu

37、e Low Limit,Angle High Limit,Angle Low Limit,Expected,拧紧错误,Angle, q,Torque, T,Crossed Threads孔直径过大,Effect on Torque/Angle End of Cycle Data:,Torque,Angle,Tightening Cycles,Torque High Limit,Torque Low Limit,Angle High Limit,Angle Low Limit,Expected,Angle, q,Torque, T,Joint Component Fails零部件连接错误,拧紧错

38、误,Effect on Torque/Angle End of Cycle Data:,Torque,Angle,Tightening Cycles,Torque High Limit,Torque Low Limit,Angle High Limit,Angle Low Limit,Expected,Angle, q,Torque, T,Stripped Threads多方面的滑扣,拧紧错误,Effect on Torque/Angle End of Cycle Data:,Torque,Angle,Tightening Cycles,Torque High Limit,Torque Low

39、 Limit,Angle High Limit,Angle Low Limit,Expected,Angle, q,Torque, T,Warped Mating Parts要与外包部件匹配,拧紧错误,Effect on Torque/Angle End of Cycle Data: 扭矩/角最终的循环数据的作用:,Torque,Angle,Tightening Cycles,Torque High Limit,Angle High Limit,Angle Low Limit,Torque Low Limit,All final cycle data is good所有的数据是有效的,Expected期望,案例分析,客户 : Swaraj Engines Ltd S发动机有限公司 问题 : Cylinder Head Leakage缸盖渗漏 分析 : Method of Tightening : Run down with Impact