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1、1-1,BASIC TIGHTENING TECHNIQUE基本拧紧技术,AC Tightening Technique阿特拉斯科普柯拧紧技术,1-2,基本拧紧技术,介绍装配过程中的基本问题，为正确和使用选择工具提供指导,对客户来讲，成功的关键是所使用的工具设备能够匹配其特定需要,1-3,Different ways of assembling装配的不同方法,Welding(焊接) Gluing(粘接) Riveting(铆接) Tightening with screws and bolts(螺栓拧紧连接),1-4,Why use bolted joints?为什么使用螺栓连接,Easy a
2、nd quick assembly(简单方便) Can be disassembled and reassembled(可以拆卸和重新装配) Standardised well-defined element(标准化) Cost-efficient(节省成本) The bolt should be weakest link(设计成最薄弱环节),Its so easy that a child can do it,1-5,The thread creates the clamp load that holds the joint together螺纹建立夹紧载何使得工件被夹紧),Clamping
3、 force,Tension,Turning the nut or screw stretches the screw(旋转螺母或者螺栓拉深螺栓) Stretching the screw clamps the parts together(拉伸螺栓保证工件夹紧) The clamp load in the joint is the target of all tightening(夹紧载何就是我们的拧紧的目标),1-6,Clamping force vs tensile load and shear load夹紧力和螺栓张力和剪切力,Clamping force,1-7,This must
4、be avoided!这个必须要避免,Shear load,Shear load,Tension,Tension,1-8,1-9,Bolt tension = 20 kN,1-10,Bolt tension = ?,ton,1-11,Bolt tension = ?,ton,= 10 kN,1-12,Is the bolt tension now approximately.现在螺栓的拉伸力大约是多少?,10 kN? 20 kN? Or 30 kN?,1-13,The Correct answer is: 正确的答案是:,20 kN the bolt pretension will NOT c
5、hange (much)螺栓上承受的拉伸力是不会变化的,1-14,The Special Fastener 特殊模式,1-15,The Use of the Special Fastener拧紧这个模式,1-16,The Joint Loaded by an Applied Force连接负载被一应用的力产生,1-17,The Joint Loaded by an Applied Force,Zero clamp at the interface. 界面中没有夹紧,1-18,The Joint Loaded by an Applied Force,1-19,Question,What is t
6、he major difference between a bolted joint on one hand and a welded, glued or riveted joint on the other hand?螺栓连接和焊接铆接粘接有什么最大的区别 And what is the consequence of this difference?这个不同点有什么重要的,1-20,Question,What is the major difference between a bolted joint on one hand and a welded, glued or riveted jo
7、int on the other hand? THE BOLTED JOINT IS PRELOADED!螺栓连接有预加负载 And what is the consequence of this diffference?,1-21,Question,What is the major difference between a bolted joint on one hand and a welded, glued or riveted joint on the other hand? THE BOLTED JOINT IS PRELOADED! And what is the consequ
8、ence of this diffference? ONLY A SMALL PORTION OF THE EXTERNAL LOAD IS TRANSFERRED TO THE BOLT (until the preload is exceeded) !只有很小的一部分外部负载被转移到螺栓上(直到超过预加负载),1-22,Question,What is the major difference between a bolted joint on one hand and a welded, glued or riveted joint on the other hand? THE BOLT
9、ED JOINT IS PRELOADED! And what is the consequence of this diffference? ONLY A SMALL PORTION OF THE EXTERNAL LOAD IS TRANSFERRED TO THE BOLT! INTERESTING BUT WHAT IS THE VALUE OF THAT? 意义-但是这个价值是什么,1-23,Variations in external loads are only to a small extent transferred to the bolt = The fatigue res
10、istance of the bolt becomes very high 外部负载的变化只有很小的一部分会转移到螺栓上=这样螺栓就不容易由于负载的交变而产生疲劳损坏 It provides a frictional grip = It will not come apart if the parts cannot move in relation to each other 提供了一个有摩擦力的夹紧=这将不会出现部件分离如果部件不能有相互的位移,1-24,螺栓连接的受力,剪切,拉伸,1-25,一定要确保施加的扭矩达到最小需要扭矩,夹紧力一定要高于外部载荷 安全余量载荷的影响因素: 振动 摩擦
11、力的变化 连接件尺寸变化 拧紧精度,1-26,施加的力不要超过使用极限,螺栓拉伸量,N 夹紧力,施加的力过大会使螺栓过度伸长 安全余量取决于: 拧紧精度 材料等级,27,螺栓连接应用的历史背景,28,历史背景,十九世纪工业革命开始，为得到更大的生产力要求工业产品必须达到： 系统化 质量可控性 可复制性,29,连接图,德国人Rotscher 在1927年提出了连接图，这种方法直到今天仍在使用，帮助我们理解连接的力学特性和进行计算。,30,VDI 2230， 德国工程师协会 2230标准,基于从1960年代就开始的研究，德国工程师协会(VDI， German Society of Engineer
12、s)发布了VDI2230：高负荷连接的系统计算方法 Systematic Calculation of High Duty Joints.,31,VDI 2230使用范围,VDI 2230的应用非常广泛，包括带60度法兰的高强度螺拴，螺丝大小从M4到M39。 它给出的是单螺拴连接的分析指导。由多个螺拴组成的连接，负荷首先要被分配，使每个螺拴上的负荷确定下来。,1-32,连接件图,螺拴与连接件的关系,拉伸弹簧压紧弹簧,1-33,螺拴和连接的变形,1-34,连 接 图 解,螺栓连接的变形关系,夹紧力,变形,预紧力,螺栓伸长1,连接件,压缩2,1-35,Joint Diagrams 连 接 图 解,
13、轴向工作载荷的影响,力,1,2,变形,螺栓受力增加部分,夹紧力 减少部分,1,工作载荷,1-36,通过螺纹产生夹紧力把连接件夹紧,旋转螺母或螺丝使螺丝受力伸长 螺丝伸长产生的夹紧力把连接件夹紧 我们需要的是连接件中的夹紧力,1-37,Torque measurement扭矩测量,The applied torque is measured应用力矩,Clamping force Needed需要的夹紧力,Clamping force is the aim at but it is hard to measure. Torque is easy to measure and apply.夹紧力是目
14、标但是比较难测量但是扭矩 比较容易测量,1-38,Torque T=Fxr,r,F,Ta, r,F,Tb,Result: Ta= 2 Tb,F = applied force (in Newton) r = lever length (in meters),1-39,为了拧紧螺栓, 必须施加力以便拧紧螺母/螺丝,1-40,Clamping force depends on torque and other factors 夹紧力的因素是扭矩和其余的因素,Fm= T/ (0.16P + (g * 0.58 * d2) + (Dkm/2) * k) Definitions: Fm = clampi
15、ng force夹紧力 P = pitch of thread螺距 g = friction value in thread;螺纹摩擦系数 d2 = diameter bolt螺纹中径 Dkm= size of surface bolt (nut)-head螺栓头小表面尺寸 Dkm = (dw + dh)/2 k= friction value surface bolt-head螺栓头下的摩擦系数,1-41,Friction between thread bolt and thread nut螺纹和螺帽的摩擦力,Clamping force夹紧力,Friction under bolt-hea
16、d 螺栓头下的摩擦力,50%,40%,Relation between applied torque and clamping force扭矩和摩擦力的关系,1-42,Changing friction:bolt-head螺栓头下的摩擦力变化,Teflon washer塑料惦片,1-43,40 %,20 %,40 %,40%,40%,Teflon washer塑料垫片,Friction between thread bolt and thread nut螺纹和螺帽的摩擦力,Clamping force夹紧力,Friction under bolt-head 螺栓头下的摩擦力,Relation between applied torque and clamping force扭矩和摩擦力的关系,1-44,Less friction:,1-45,Changing friction:bolt-he
