atlascopco基本擰緊技術(shù)ppt課件

1、1-1,BASIC TIGHTENING TECHNIQUE基本擰緊技術(shù),AC Tightening Technique阿特拉斯·科普柯擰緊技術(shù),1-2,基本擰緊技術(shù),,介紹裝配過(guò)程中的基本問(wèn)題，為正確和使用選擇工具提供指導(dǎo),對(duì)客戶來(lái)講，成功的關(guān)鍵是所使用的工具／設(shè)備能夠匹配其特定需要．,,1-3,Different ways of assembling裝配的不同方法,,Welding(焊接)Gluing(粘接)Riv

2、eting(鉚接)Tightening with screws and bolts(螺栓擰緊連接),1-4,Why use bolted joints?為什么使用螺栓連接,,Easy and quick assembly(簡(jiǎn)單方便)Can be disassembled and reassembled(可以拆卸和重新裝配)Standardised well-defined element(標(biāo)準(zhǔn)化)Cost-efficien

3、t(節(jié)省成本)The bolt should be weakest link(設(shè)計(jì)成最薄弱環(huán)節(jié)),,It’s so easy thata child can do it,1-5,The thread creates the clamp load that holds the joint together螺紋建立夾緊載何使得工件被夾緊),Clamping force,Tension,,Turning the nut or screw

4、 stretches the screw(旋轉(zhuǎn)螺母或者螺栓拉深螺栓)Stretching the screw clamps the parts together(拉伸螺栓保證工件夾緊)The clamp load in the joint is the target of all tightening(夾緊載何就是我們的擰緊的目標(biāo)),,1-6,Clamping force vs tensile load and shear lo

5、ad夾緊力和螺栓張力和剪切力,,,,,,,,,,,,,,Clamping force,,1-7,This must be avoided!這個(gè)必須要避免,,,,,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

6、-12,Is the bolt tension now approximately……..現(xiàn)在螺栓的拉伸力大約是多少?,10 kN? 20 kN?Or 30 kN?,1-13,The Correct answer is: 正確的答案是:,20 kN – the bolt pretension will NOT change (much)螺栓上承受的拉伸力是不會(huì)變化的,1-14,The Special Fastener特殊模式,1

7、-15,The Use of the Special Fastener擰緊這個(gè)模式,1-16,The Joint Loaded by an Applied Force連接負(fù)載被一應(yīng)用的力產(chǎn)生,1-17,The Joint Loaded by an Applied Force,Zero clamp at the interface.界面中沒(méi)有夾緊,,1-18,The Joint Loaded by an Applied Force,1-

8、19,Question,What is the major difference between a bolted joint on one hand and a welded, glued or riveted joint on the other hand?螺栓連接和焊接鉚接粘接有什么最大的區(qū)別And what is the consequence of this difference?這個(gè)不同點(diǎn)有什么重要的,1-20,Quest

9、ion,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!螺栓連接有預(yù)加負(fù)載And what is the consequence of this diffference?,1-21,Qu

10、estion,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 consequence of this diffference?ONLY A SMALL

11、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負(fù)載被轉(zhuǎn)移到螺栓上(直到超過(guò)預(yù)加負(fù)載),1-22,Question,What is the major difference between a bolted joint on one hand and a welded, glued or

12、riveted joint on the other hand?THE BOLTED 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 O

13、F THAT? 意義-但是這個(gè)價(jià)值是什么,1-23,,Variations in external loads are only to a small extent transferred to the bolt => The fatigue resistance of the bolt becomes very high外部負(fù)載的變化只有很小的一部分會(huì)轉(zhuǎn)移到螺栓上=>這樣螺栓就不容易由于負(fù)載的交變而產(chǎn)生疲勞損壞It p

14、rovides a frictional grip => It will not come apart if the parts cannot move in relation to each other提供了一個(gè)有摩擦力的夾緊=>這將不會(huì)出現(xiàn)部件分離如果部件不能有相互的位移,1-24,螺栓連接的受力,剪切,拉伸,1-25,一定要確保施加的扭矩達(dá)到最小需要扭矩,,夾緊力一定要高于外部載荷安全余量載荷的影響因素:振動(dòng)

15、摩擦力的變化 連接件尺寸變化擰緊精度,1-26,施加的力不要超過(guò)使用極限,螺栓拉伸量,N夾緊力,施加的力過(guò)大會(huì)使螺栓過(guò)度伸長(zhǎng)安全余量取決于:擰緊精度材料等級(jí),27,,螺栓連接應(yīng)用的歷史背景,28,歷史背景,十九世紀(jì)工業(yè)革命開(kāi)始，為得到更大的生產(chǎn)力要求工業(yè)產(chǎn)品必須達(dá)到：系統(tǒng)化質(zhì)量可控性可復(fù)制性,29,連接圖,德國(guó)人Rotscher 在1927年提出了連接圖，這種方法直到今天仍在使用，幫助我們理解連接的力學(xué)特性和進(jìn)行計(jì)算。

16、,30,VDI 2230， 德國(guó)工程師協(xié)會(huì) 2230標(biāo)準(zhǔn),基于從1960年代就開(kāi)始的研究，德國(guó)工程師協(xié)會(huì)(VDI， German Society of Engineers)發(fā)布了VDI2230：高負(fù)荷連接的系統(tǒng)計(jì)算方法 － Systematic Calculation of High Duty Joints.,31,VDI 2230－使用范圍,VDI 2230的應(yīng)用非常廣泛，包括帶60度法蘭的高強(qiáng)度螺拴，螺絲大小從M4到M39。它給出

17、的是單螺拴連接的分析指導(dǎo)。由多個(gè)螺拴組成的連接，負(fù)荷首先要被分配，使每個(gè)螺拴上的負(fù)荷確定下來(lái)。,,1-32,連接件圖,螺拴與連接件的關(guān)系,拉伸彈簧＋壓緊彈簧,1-33,螺拴和連接的變形,1-34,連 接 圖 解,螺栓連接的變形關(guān)系,夾緊力,變形,預(yù)緊力,螺栓伸長(zhǎng)δ1,,連接件,壓縮δ2,1-35,Joint Diagrams連 接 圖 解,軸向工作載荷的影響,力,δ1,,δ2,,變形,螺栓受力增加部分,夾緊力減少部分,,,,,σδ1

18、,,,工作載荷,,,1-36,,,通過(guò)螺紋產(chǎn)生夾緊力把連接件夾緊,旋轉(zhuǎn)螺母或螺絲使螺絲受力伸長(zhǎng)螺絲伸長(zhǎng)產(chǎn)生的夾緊力把連接件夾緊我們需要的是連接件中的夾緊力,,1-37,Torque measurement扭矩測(cè)量,,,,,,,,,,,,,,The applied torque is measured應(yīng)用力矩,Clamping forceNeeded需要的夾緊力,,Clamping force is the aim at but

19、it is hard to measure.Torque is easy to measure and apply.夾緊力是目標(biāo)但是比較難測(cè)量但是扭矩比較容易測(cè)量,1-38,Torque T=Fxr,,,,,r,,F,,Ta,,,,½ r,,F,Tb,,Result: Ta= 2 Tb,F = applied force (in Newton)r = lever length (in meters),1-39,為了擰緊

20、螺栓, 必須施加力以便擰緊螺母/螺絲,1-40,Clamping force depends on torque and other factors 夾緊力的因素是扭矩和其余的因素,Fm= T/ (0.16P + (μg * 0.58 * d2) + ((Dkm/2) * μk))Definitions:Fm = clamping force夾緊力P = pitch of thread螺距μg = friction

21、 value in thread;螺紋摩擦系數(shù)d2 = diameter bolt螺紋中徑Dkm= size of surface bolt (nut)-head螺栓頭小表面尺寸Dkm = (dw + dh)/2 μk= friction value surface bolt-head螺栓頭下的摩擦系數(shù),1-41,,,,Friction betweenthread bolt andthread nut螺紋和螺帽的摩

22、擦力,Clamping force夾緊力,Friction under bolt-head螺栓頭下的摩擦力,,,50%,40%,Relation between applied torque and clamping force扭矩和摩擦力的關(guān)系,1-42,Changing friction:bolt-head螺栓頭下的摩擦力變化,Teflon washer塑料惦片,,1-43,,,,40 %,20 %,40 %,,,,,,40%

23、,40%,,Teflon washer塑料墊片,Friction betweenthread bolt andthread nut螺紋和螺帽的摩擦力,Clamping force夾緊力,Friction under bolt-head螺栓頭下的摩擦力,Relation between applied torque and clamping force扭矩和摩擦力的關(guān)系,1-44,Less friction:,,1-45,Chan

24、ging friction:bolt-head螺栓頭下的摩擦力變化,Locking washer防松墊片,,1-46,,,,,,60%,40%,,Locking washer防松墊片,Friction betweenthread bolt andthread nut,Clamping force,Friction under bolt-head,Relation between applied torque and clampi

25、ng force扭矩和摩擦力的關(guān)系,1-47,More friction,,1-48,Changing friction:thread bolt - nut螺紋的摩擦力變化,1-49,,,,50 %,20 %,30 %,,,,,,50%,30%,Oil on threads,,,,Friction betweenthread bolt andthread nut,Clamping force,Friction under bol

26、t-head,Relation between applied torque and clamping force,1-50,Less friction:,,,,50 %,20 %,30 %,,1-51,Changing friction:thread bolt - nut,1-52,,,,50 %,0 %,50 %,,,,,,50%,50%,Rusted bolt,,Friction betweenthread bolt and

27、thread nut,Clamping force,Friction under bolt-head,Relation between applied torque and clamping force,1-53,More friction,,,,50 %,0%,50 %,,1-54,Other ways of changing the friction?,Liquid loctite液體樂(lè)泰螺紋膠Locknut防松螺帽P(pán)aint

28、 in the threads螺紋中含有油漆Damaged threads損壞的螺紋Welding pearls焊渣Bolt finishing (Cr6, Dacromet®, etc.),1-55,Loctite,1-56,Locknut,1-57,Paint on the threads,1-58,Damaged threads,1-59,50-40-10 規(guī)則,扭矩,100%,,,,,,,90% 的扭矩用于克服摩

29、擦力,夾緊力10%,螺紋副中40%,螺栓頭下摩擦力 50%,1-60,夾緊力與摩擦力的關(guān)系,一般情況下,螺栓頭下摩擦力50%,螺紋副中摩擦力40%,10%,在螺栓法蘭面上加潤(rùn)滑油,螺栓頭下摩擦力45%,螺紋副中摩擦力40%,夾緊力15%,螺紋副中有雜質(zhì)或螺紋受損,螺栓頭下摩擦力50%,螺紋副中摩擦力45%,5%,1-61,螺栓標(biāo)識(shí)系統(tǒng),生產(chǎn)商標(biāo)識(shí)第一個(gè)數(shù) = 1/100 的最大抗拉強(qiáng)度 (N/mm2)100&#

30、215;8 = 800 N/mm2 第二個(gè)數(shù) =屈服強(qiáng)度與最大抗拉強(qiáng)度之間的關(guān)系 0.8 = 80%兩數(shù)相乘得出屈服應(yīng)力 800* 0.8 = 640 N/mm2,,,,公制螺紋,1-62,施加的力不要超過(guò)使用極限,螺栓拉伸量,N夾緊力,施加的力過(guò)大會(huì)使螺栓過(guò)度伸長(zhǎng)安全余量取決于:擰緊精度材料等級(jí),1-63,64,,軟連接和硬連接,65,,,,,Torque = OK,夾緊角: φ,66,硬連接的定義 (I

31、SO 5393),,,,,30° max.,夾緊角,,67,硬連接舉例,,Clamping force,Steep slope,Angle,Low angle displacement,68,,,720° min.,軟連接,,軟連接的定義 (ISO 5393),69,軟連接舉例,,Clamping force,Soft slope,Angle,High angle displacement,1-70,,連接的特性也決

32、定著所需工具的類型(ISO 5393) ．,旋轉(zhuǎn)角度,目標(biāo)扭矩,A. 硬連接：到達(dá)貼合點(diǎn)后，旋轉(zhuǎn)30°以內(nèi)達(dá)到目標(biāo)扭矩的連接。B. 軟連接：到達(dá)貼合點(diǎn)后，旋轉(zhuǎn)2 圈（720°）以上達(dá)到目標(biāo)扭矩的連接。扭矩的過(guò)扭程度受連接件硬度以及工具轉(zhuǎn)速影響。,軟連接、硬連接,,,,,,,,30°,720°,71,,,,,,硬連接< 30 deg (ISO 5393),軟連接> 720 deg

33、 (ISO 5393),X Nm,X Nm,,< 30°,,> 720°,,72,扭矩過(guò)沖,10 Nm,9 Nm,工具雖然設(shè)定都是9Nm，但是針對(duì)不同性質(zhì)的連接會(huì)產(chǎn)生不同的結(jié)果,1-73,軟、硬連接,,,,,,目標(biāo),,均值偏差,扭矩,角度,過(guò)扭,,貼合點(diǎn),硬連接,軟連接,1-74,如何在一個(gè)連接件上測(cè)量扭矩,動(dòng)態(tài)扭矩:在擰緊螺栓的同時(shí)用在線式扭矩傳感器測(cè)量。 靜態(tài)扭矩:安裝后用扭矩扳手測(cè)

34、量。,1-75,靜態(tài)扭矩,動(dòng)力工具輸出扭矩 92949192949292X=92,43=1,13,扭力扳手靜態(tài)扭矩 103 106 103 100 100 103 100X=102,14=2,27,,T (Nm),時(shí)間,,20,40,60,80,100,110,120,(A)工具輸出 (動(dòng)態(tài)扭矩),,(B) 扭力扳手 (靜態(tài)扭矩),,,,,,原因:靜態(tài)摩擦

35、力,,,,76,硬連接上－－由于較高的靜態(tài)摩擦力，靜態(tài)扭矩可比動(dòng)態(tài)扭矩要高。右下圖中倒V的拐點(diǎn)即是扭力扳手測(cè)得的硬連接上的靜態(tài)扭矩,1-77,裝配手測(cè)(動(dòng)態(tài))(靜態(tài)) 102.6 112 102.6 110 101.4 111 101.2 110 102.4 113 100.9 109 102.1 110 10

36、2.4 111 101.0 113 101.8 112 101.84 111.1 0.67 1.4 2.01 4.1,均值 標(biāo)準(zhǔn)偏差 (Sigma) 3 Sigma,硬連接,78,軟連接－－靜態(tài)扭矩較動(dòng)態(tài)扭矩要偏小，原因是衰減。VDI2230里系統(tǒng)的方法設(shè)置螺拴即有計(jì)算扭矩衰減這一步驟,79,,,,If we look at what ha

37、ppens to the surface in contact with the threads and under the head, we will notice that locally the load can be extremely high, far exceeding yield and these areas will collapse (embedment). Embedment reduces the clampi

38、ng force because the elongation of the bolt is reduced.,Very high load,,,,,,,,,Average load (80% of yield),,扭矩衰減,© copyright BLM s.a.s - 24 giugno 2004,80,扭矩衰減的原因呢 – 連接的嵌入,81,,,82,Calculation Step R4 - Establishing

39、Preload Losses計(jì)算步驟R4－確定預(yù)加負(fù)荷損失,losses.由于局部嵌入和不同的熱膨脹特性，螺拴預(yù)加負(fù)荷可能會(huì)損失,Aluminium Joint,Steel Bolt,,,1-83,彈性衰減會(huì)影響夾緊力,,,,,,,,,,,,,,,,,,材料彈性衰減會(huì)使夾緊力衰減!,,Time,1-84,均值 標(biāo)準(zhǔn)偏差 (Sigma) 3 Sigma,裝配手測(cè)(動(dòng)態(tài))(靜態(tài)) 100.2 88

40、100.5 84 100.7 92 100.3 86 100.4 90 100.8 88 100.5 86 100.2 85 100.2 84 100.4 84 100.42 86.7 0.21 2.8 0.63 8.3,軟連接,1-85,衰減,60-70%的衰減發(fā)生在30毫

41、秒以內(nèi),時(shí)間,,牛米,,,,,,,衰減,斷氣,1-86,扭矩和角度 OK,,,,,,,,,,,扭矩,角度,扭矩 = OK角度 = OK,,,,,1-87,,結(jié)論：,,Clamp force,Friction in threads,Friction under nut or head,螺栓裝配質(zhì)量對(duì)產(chǎn)品的最終質(zhì)量有著直接影響,為了得到質(zhì)量合格的擰緊連接–擰緊扭矩必須精確連接件質(zhì)量必須得到監(jiān)控,88,擰緊方法的分類－按工具控制方式,

42、基于扭矩或角度:彈性范圍內(nèi):扭矩控制角度控制連接控制超出彈性范圍角度控制梯度(扭矩變化率)控制，即屈服點(diǎn)控制其他方式超聲波機(jī)械測(cè)試伸長(zhǎng)量,89,夾緊力,角度,扭矩,角度,螺拴連接模型,90,夾緊力,扭矩,角度,角度,螺拴連接模型－塑性變形階段,91,扭矩控制,92,扭矩控制方式利用的是人們熟知的扭矩與張緊力之間的關(guān)系公式。扭矩控制方式在出現(xiàn)最大摩擦系數(shù)和最小力率(Force Rate)時(shí)提供最小的夾緊力，反之亦然。,

43、扭矩控制,93,優(yōu)勢(shì):容易實(shí)現(xiàn)不同精度等級(jí)的控制+/-25%的脈沖型工具到+/-1%的擰緊軸巨量的產(chǎn)品和過(guò)程設(shè)計(jì)的標(biāo)準(zhǔn)數(shù)據(jù)-歷史悠久過(guò)程和設(shè)備的有效性校驗(yàn)過(guò)程非常容易 工程師非常熟悉，廣為人知,扭矩控制,94,Tightening Methods,劣勢(shì): 夾緊力的精度很差,可能到+/- 60 %,受摩擦系數(shù)影響大 沒(méi)有根本辦法防止螺拴斷裂以上兩個(gè)原因?qū)е侣菟┠芰寐实?－ 60%,扭矩控制,95,彈性區(qū)域角

44、度控制,擰緊規(guī)范=門檻力矩+擰緊角度,96,彈性區(qū)域內(nèi)的角度控制避免了的摩擦系數(shù)大范圍變動(dòng)對(duì)夾緊力的影響。它通過(guò)控制轉(zhuǎn)角來(lái)擰緊，利用了力率變動(dòng)較小的優(yōu)勢(shì)。,零件開(kāi)始被壓在一起,角度,扭矩,,彈性區(qū)域角度控制,討論：力率 Force Rate 是什么？影響它的主要因素有哪些？,97,優(yōu)勢(shì) 相對(duì)容易實(shí)現(xiàn) 過(guò)程和產(chǎn)品的有效性相對(duì)容易檢查 現(xiàn)場(chǎng)維修的成本和精度可以接受 螺拴利用率得到大大提高,彈性區(qū)域角度控制,98,

45、劣勢(shì) 標(biāo)準(zhǔn)的擰緊規(guī)范通常不能直接使用了－必須做一些連接分析/實(shí)驗(yàn)室分析工作 無(wú)法使用扭力扳手復(fù)緊來(lái)校驗(yàn) 工具同時(shí)需要扭矩和角度測(cè)量能力,彈性區(qū)域角度控制,99,夾緊力,扭矩,角度,角度,,門檻力矩,,,,,擰緊角度,夾緊力變化,塑性區(qū)域角度控制,100,優(yōu)勢(shì) 摩擦力影響降到最低 最大程度上利用螺拴能力,劣勢(shì)生產(chǎn)條件下檢驗(yàn)工具性能很困難設(shè)置和校驗(yàn)產(chǎn)品參數(shù)的費(fèi)用較高螺拴一般無(wú)法重復(fù)使用,塑性區(qū)域角度控制,

46、101,扭矩,dT/dA 最大值,dT/dA 最大值 的某個(gè)百分比,dT/dA,角度,角度,梯度(扭矩變化率)控制、屈服點(diǎn)控制,102,優(yōu)勢(shì) 螺拴進(jìn)入塑性階段一個(gè)小角度,最大程序利用螺拴 螺拴可以重復(fù)利用幾次 夾緊力精度很高,擰緊效果不受彈性系數(shù)即力率Force Rate K的影響.當(dāng)需要用許多螺拴堅(jiān)固的情況下,如氣缸蓋,在設(shè)計(jì)上有時(shí)需要對(duì)不同位置使用不同螺拴,彈性系數(shù)不同.但這只影響屈服點(diǎn)的角度,夾緊力最大值總是在屈服點(diǎn)

47、附近.,梯度(扭矩變化率)控制、屈服點(diǎn)控制,103,劣勢(shì) 需要連接分析和實(shí)驗(yàn)室工作 過(guò)程的檢驗(yàn)困難 擰緊/修復(fù)螺拴可能是個(gè)問(wèn)題 設(shè)備昂貴,梯度(扭矩變化率)控制、屈服點(diǎn)控制,104,超聲波提供了最精確的夾緊力測(cè)量方式，把它作為擰緊控制方式效果也最好。但使用這種方式需要滿足許多特殊條件：聲耦合， 螺拴長(zhǎng)度直徑比，螺拴頭尾的特殊處理等。由于這些條件很難在生產(chǎn)條件下滿足，所以目前只限于實(shí)驗(yàn)室分析使用。,其他控制方式－超聲波測(cè)