1_1基本拧紧技术讲解

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螺纹紧固件
Threaded fasteners - Torque
夹紧力是我们的目标，但是很难测量，而扭矩很容易测量
Clamp force is what we aim at but it is difficult to be measured. Torque is easy to measure and to apply
– – – – – Fm P μg d2 Dkm = 夹紧力clamping force = 螺距pitch of thread = 螺纹副摩擦系数friction value in thread = 螺栓直径diameter bolt =螺栓头表面尺寸 size of surface bolt (nut)-head
• •
螺栓标记Bolt marking 螺栓分级Screw classifications
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什么是连接
What is a joint?
螺栓Screw
连接件Joining parts
螺母Nut
连接受到不同的外力The joint is exposed to different external forces
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生产过程中的几种装配方法assembly
• • • • 焊接 粘接 铆接 用螺丝和螺栓拧紧
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哪种装配方法最普遍？Which one is most common
• • • • 焊接 粘接 铆接 用螺丝和螺栓拧紧
?
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使用螺丝和螺栓拧紧！Advantages with screws and bolts!
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这种情况必须避免This must be avoided!
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The thread creates the clamp force that holds the joint together
• Turning the nut or screw stretches the screw • The stretching of the screw clamps the parts together • The clamp force in the joint is the target of all tightening
螺纹副摩擦力Friction in the threads
50 – 40 – 10 规则
541rule
螺栓头下摩擦力 Screw head friction 50%
产生夹紧力
Clamp Force
10% 90% 的扭矩用于克 服摩擦力
螺纹副中
Friction in the threads
40%
扭矩
100%
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夹紧力取决于扭矩和其他因素-摩擦力
Clamping force is dependent of torque and other factors – mainly friction
• Fm= T/ (0.16P + (μg * 0.58 * d2) + ((Dkm/2) * μk)) 螺距Pitch 螺纹副Thread 螺栓头Head • 定义Definitions
基本拧紧技术
Basic tightening technique
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目的与概要Purpose
• 掌握以下几个要点，并能与客户就生产中的相关问题进行解释， 为客户提供正确的工具和方案作指导 • 内容Content
– 螺纹紧固件thread joint – 什么是连接件？joint – 扭矩，摩擦力和夹紧力的关系torque, friction and clamp force – 关于扭紧的几个基本概念tightening conception – 抗拉强度和屈服点tensile stress and yield
20 %
40 %
螺纹副摩擦力Friction in the threads
40 %
塑料垫圈plastic washer 40%
40%
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改变摩擦力 – 加润滑friction change-lubrication
螺纹里的润滑lubrication
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扭矩和夹紧力的关系torque and clamp force
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施加100%扭矩，夹紧力的结果Applied Torque (100%) and resulting Clamp Force…
‘正常情况Normal conditions’
扭矩Torque 螺栓头摩擦力Screw head friction
夹紧力Clamp Force
10% 100 %
50%
40%
!
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基本拧紧技术Basic tightening technique
• • • •
• • •
什么是连接What is a joint? 部件Parts 不同的连接Different joint types 不同的负载Different loads
扭矩、摩擦力和加紧力Torque, friction and clamp force 连接类型Joint types 抗拉强度和屈服点Tensile stress and yield point
施加的扭矩The applied torque is measured
夹紧力是我们的目标Clamp force
is our target
1 0
直接测量夹紧力的方法the way to measure clamp force
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为了拧紧螺栓, 必须施加力以便拧紧螺母/螺丝
The applied torque is must
But why? • • • • • • 设计简单Simplicity of design 零部件标准化Standardized 装配简单，拆卸方便（可逆）Easy assembly and disassembly 效率高High productivity 成本低COST efficient 可控（螺栓张力可控）well controlled
= 螺栓头表面摩擦系数fricition value surface bolt-head
• Dkm = (dw + dh)/2
– μk
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改变摩擦力 –塑料垫圈friction chanቤተ መጻሕፍቲ ባይዱe-plastic washer
夹紧力Clamp Force
螺栓头摩擦力Screw head friction