关于焊接滚轮架轴向窜动的实验研究外文文献翻译@中英文翻译@外文翻译

Jounal of matenals processing technology 63 (1997) 881-886 Experiment and study into the axial drifting of the cylinder of a welding rollerbed Fenggang shen ,xide pan ,jin xue Welding research instiute ,xian jiaotong university. Xian .shaanxi province 710049.P.R.china Abstract The basic theory of the axial drifting of the cylinder of a welding roller bed is introduced in the paper,and at the same time experiment and study on the mechanism of the axial drifting of the cylinder have been done on an experimental model of the welding roller bed . It is shown that the main cause of the axial drifting of the cylinder lies in the existence of a spiral angle between the cylinder and the cylinder and the roller . the relative axial motions between the roller and the cylinder are compose of spiral motion,elastic sliding and frictional sliding. The theory of compatible motion and non-compatible motion is put forward for the axial motions of the cylinder .the relative axial motions of the cylinder . The relative axial motion between the rollers and the cylinder is coordinated by elastic sliding and frictional sliding between them Keywords: welding roller bed； cylinder ； roller ； axial motion ； spiral angle 1 Introduction In welding production, the assembly and circular seam welding of rotary workpieces, such as a boiler, a petrochemical pressure vessel and so on, are conducted on ；a welding roller bed. When rotating On a welding roller bed. The cylinde will inevitably produce axial drifting due to manufacturing, assembling tolerance of the welding roller bed and the cylinders surface irregularity (divergiug froman ideal rotary workpiece), thus the welding procedure may not be carried out successfully. It is necessary, therefore, to study the mechanism of the axial drifting of the cylinder to solve the problem of the axial drifting of the cylinder in circumferential welding. The results of the research will benefit the studying and designing of antidrifting welding roller bed. especially the analysis of the applied forces on the bed, and lead to determining the manufacturing and assembling tolerance of the bed, and providing the basis of theory for the mechanical adjusting mode to avoid axial drifting, the adjusting mode of closed circuit in the control circuit, and the selection of the adjusting value. 2. Theoretical analysis 2.1. Welding roller bed and cylinder A welding roller bed is generally composed of four rollers. Driven by the driving roller, the cylinder makes a rotary uniform motion around its axis(shown in Fig. I), during which the circumferential welding procedure is carried out In Fig.1, a is the central angle, S is the supporting distance, L is the span of the roller. and V, is the circular linear velocity of the cylinder, also named the welding velocity2. The axis of the cylinder will be not parallel to that of a roller if the roller is deflected by a certain angle from the deal position, or if the centers of the four rollers lie in the vertices of a simple quadrilateral, or if the centers of the four rollers are not on the same plane, or if the circu- larity of the cylinder is irregular because of deviation in manufacturing and assembling. Thus. the cylinder will nevitably move along its axis when rotating on a bed the contact of the cylinder and a roller can be cansidered as point contact if cytinders axis and rollers axis do not lie in the same plane. Suppose P is the point of contact. the cylinders normal plane A is defined by the plane on which are the cylinders axis and generatrix n across the point of tangency on the cylinder (shown in fig2) makea cylinders tangent plane B across point P. Thus, plane A is vertical to plane B. lc is a cylinders tangent across P and lies in plane B. Ir is the rollers tangent across the same point P, and lies in plane B also. In general, is defined as the axial deviation angle between the rol!ersaxis and the cylinders axis； is defined as the spiral angle between generatrix n and m . a projective line obtained by projecting the rollers generatrix m across point p on plane B and is defined as the projective angle between n and m , a projective line obtained byprojecting m on plane A. Fig. 3 indicates that the rela- tionship amongst the three angles is tan = tan2 - tan 2 In Fig. 3, SB, S and S, are called the spiral displace-ment vector, the axial deviation displacement vector and the projective displacement vector respectively. their relationship being: Fig. 2 Geometric relationship between the cylinder and an individual roller Fig. 3 Relationship between the angle vector and the displacement vector 2.2.2 relative axial motions relationship (1)spiral motion2. Fig. 4 Component of axial velocity Because the rollers axis is not parallel to the cylin- ders central line, there is a spiral angle between Vr,. and Vc, on the point of contact (shown in Fig. 2). When the roller and cylinder rotate synchronistically around their own axes, driven by tangential frictional force. a spiral effect will occur because of the different linear velocity direction between the roller and the cylinder at point P of contact The cylinder has a component of axial velocity, where Vc is the circular linear velocity of the cylinder. is the cylinders axial component velociry exerted by single roller, and j can be 1. 2, 3, 4, representing the four rollers, respectively. (2) Elastic sliding Because of the existence of a spiral angle, an axial force Faj acts on cylinder. When the force is less than the maximum axial frictional force fNj (where f is the frictionfactor, and Nj is the normal pressure between a single roller and the cylinder), the cylinder will slide elastically over the roller along the axial direction23 The component of the sliding velocity is. where e is the elastic sliding factor for metallic roller. e=O.OOl 0.005. (3) Frictional sliding When Faj is greater than the maximum frictional force fNj, the cylinder will make a frictional sliding over the roller. The sliding resistance is fNj3. The component of the frictional sliding velocity on Cylinder is Vaj the magnitude and direction of which can be determined by the universal relationship between the cylinder and the four rollers Frictional sliding will lead to the wear and tear of the surface of the cylinder and the rollers. which is unexpected in welding production When the cylinder drifts, above three kinds of motion do not occur simultaneously Ihereforc. the axial drifting velocity of the cylinder is not the algebraic sum of the three components of velocity In the case of elastic sliding, the axial velocity is. 2.3 axial motion of the cylinder on a welding roller bed 2.3.1 Axial compatible motion Under ideal conditions, when spiral angles j between the cylinder and the four rollers are all the same, that is: 1= 2= 3= 4= the cylinder will move its compatible spiral motion. Two categories can be classified to analyze the axial motion of the cylinder: (I) When there does not exist an axial component due to gravity. the cylinders axial drifting velocity is: Va=Vc * tan (2) When there exists an axial component of gravity Ga there exists an axial force on the cylinder. Now, the axial forces exerted on the four rollers have the same directional And magnitude, the value being equal to Ga besues the component of spiral vetocity, there exist component of elastic on the cylinder the cylinders axial drifting velocity is 2.3.2.axial non-compatible motion In general. spiral angles j between the cylinder and the four rollers are not equal to each other in size and direction. i .e. the geometric relationships between the cylinder and the four rollers are all inconsistent Therefore, the components of the cylinders axial velocity against four rollers (i.e Vc *ta j) are not identical to each another. The cylinder will move with axial nompatible motion The axial velocities of the cylinder againsa the four rollers should be the same because the cylinder is considered as a rigid body as a whole and it has only one axial velocity. However. for some roller, Vc . tan j and the cylinders real axial velocity are not likely to be the same, so an axial frictional force almost certainly appears between this roller and the cylinder The following two categories can be classified to discuss the non-compatible axial motion of the cylinder according to Ihe frictional forces magnitude: (I) When the axial frictional forces erected by each roller and the cylinder are all less than the maximum axial the action of the cylinder against the frictional force the action of the cylinder against the rollers produces elastic sliding The axial motion betweenan individual roller and the cylinder is coordinated by their elastic sliding when the axial velocity of the cylinder is constant, the algebraic sum of cylinders axial forces erected by four rollers should be zero if rhe axial component of gravity is ignored. i.e. and there is little difference amongst Nj, against the four rollers, so that they can be approximately regarded as the same. Thus: according to the above two equations, the axial drifting velocity of the cylinder is. Where 0.25Tant represents the intrinsic attributes of the welding. Other bed under the condition that only the cylinder against all rolls produces elastic sliding this may be called the spiral rate of the cylinders spiral motion (2) When the axial frictional force erected by some roller and the cylinder is greater than the maximum axial frictional force, frictional sliding occurs between the cylinder and this roller Then. the maximum axial force is acting on the bearing of the roller, its value being Ffmax=fFNfmax Because of the esistence of this frictional sliding. the Axial motion between an individual roller and the cylinder is not coordinated by their elastic sliding Now the axial non-compatible motion of the cylinder is determined by the relative relationships between the cylinder and the four rollers. It is difficult to write a general compatible equation of the cylinders axial drifting velocity because this kind of condition is very complex. The following is further analysis and discussion of the problem At first, for ease in analyzing problem, the spiral angle average is defined as and the relative spiral angle as Arrange ,1 in the order from big to smll and then from posirive to negative, expressed as (j). then 1234 Similarly, the normal force between the cylinder and a roller can be expressed as N(j). and the axial force as FjfNj In general, the axial motion of the cylinder determined by the spiral angle average is definel as the compatible component of the axial motion, is velocity being The axial motion of the cylinder determined by the relative spiral angle j is defined as the non-compatible component of axial motion, its velocity being expressed asVan Analysis shows that Va is determined by the equilibrium condition the four roller axial forces when the cylinder moves along axial direction at a constant velocity. where not taking into account of the function of gravitys axial component. Supposing that the cylinder makes a non-compatible component of axial motion with the maximum relative spiral angle (I). its velocity is Then the four axial forces can not be in equlibrium .i.e F1-(F2+F3+F4) 0 Because there is little difference amongst four normal forces, the four axial farces are also determined by normal force and the friction factor any axial force undoubtedly being less than the sum of the other three forces. Otherwise, if the cylinder makes a non-compatible component of axial motion with the minimum relative spiral angle (4). its velocity is. Va” = Vc * tan(4) Similarly. four axial forces can not be in equilibrium also, i.e. : F(l) + F(2) + F(3) J - F(4) 0 Therefore, the cylinder can only be approximately considered as making a non-compatible component of axial motion with the second or third relative spiral angle, i.e.: In whatever case as expressed above. when the cylinder make a non-compatible component of axial motion, thetwo rollers having a greater velocity are driving rollers,and the other two rollers having a lesser velocity are resistant rollers, the equilibrium condition of axial forces being operative, i.e.: F(1) + F(2) = F(3) + F(4) According to the analysis above, and because of the unstability of friction factor f that is affected by the factors of load, material, condition of the contact surface, and circumstance, the non-compatible component Va of the axial velocity of the cylinder is undefined. When the cylinder makes a non-compatible axial motion, its axial velocity is composed of a compatible component Va 0 and a non-compatible component Va n i.e Va=Va0+Van Va=Va0+Van The most optimal adjustment of the axial motion is to make the non-compatible component as small as possible according to the stability of adjustment and decrease in axial force. No matter whether the cylinder makes compatible or non-compatible motion, supposing that the cylinder is ideal, its axial velocity is always existent and definable for a particular bed, its magnitude and direction reflecting the beds inherent property. 3. Experiment 3.1. Descriphm of experment The experimental model is shown in Fig 5. Experiments were done to study two factors: the spiral angle and the cylinders circular linear velocity, which affect the axial drifting of the cylinder. In the experimenting process. the axial displacement Sa and the axial drifting velocity Va of the cylinder were measured by the variation of the two factors described above. The measuring method is shown in Fig. 5, and is carried out by means of bringing an axial displacement sensor into contact with one end of the cylinder. with the sensor being connected to an X-Y recorder to record the cylinders axial displacement every 5s. Linearly regressing the plot Sa-t (t expresses time), the average drifting velocity Va , at every deflecting angle can be calculated. Before experimenting. the experimental model is initialised as follows: first. the height of the four rollers is adusted by means of a level to put the centers of the four rollers in the same horizontal plane, and at the four vertexes of the rectangle. then the rollers are deflected so that the rotating cylinder is at the relative equilibrium position. Then the cylinder does not drift over a long time. or periodically drift over a very small axial range 3.2 experiment results and discussion 3.2.1 Effect of spiral angle (I) Fig. 6 shows that change of Va with the variation ofThe testing condition is: positive rotalion, Vc=35m/h L=422mm, =60” The Va -tan 4 curve shows that Va is directly proportional to tan 4 when 4 is relatively small (16c ). The slope of the line being 3. 06 mm/s, Va is no longer direclly proportional to tan 4 when 4, is greater than 6C The curve is an arched curve. i. e . with the increment of 4,.Va , increases. but with the increment of Va gradually becoming smallet Because only one driven roller (roller No. 4) is deflected, i.e 4 can be changed whilst the others remain zero, the cylinder makes a non-compatible motion. When 4 is relatively small, Va is small also. The axial frictional forces between the cylinder and rollers are less than the maximum axial frictional force, and the cylinder produces an elastic sliding against rollers. Axial motion between each roller and the cylinder is coordinated by elastic sliding. thus Va is: in the theoretical curve, the slope K can be calculated by the following equation: K=3.06mm/s in the experimental curve. Thus, in taking account of the experimental tolerance, the two slopes can be considered to be approximately equal. When 4 is relatively large, the axial frictional forces between the cylinder and the rollers are larger than the maximum axial frictional Force, and cylinder produces frictional sliding against the rollers Because of Ihe existence of sliding frictional resistance. Va is no longer lincarty increased with the increment of tan 4 With the increment of tan 4 the increment of V a； with gradually become smaller (2) The following three experiments were arranged to study the cylinders non-compatible axial motion further, deflecting positively one roller. two rollers and three rollers by the same spiral angle to measure three curves between Sa and v The experimental results are shown in Fig 7. With the increment in the number of deflected rollers, Va becomes greater. i e Va 3 Va 2 Va1 When the number of driven rollers deflected is varied, the degree of the cylinders non-compatible axial motion will be changed. With the increment of the number of lollers deflected by the same spiral angle. the compatible component becomes greater, but the non-compatible component becomes smaller. In other words, the cylinders axial motion will be transformed from noncompatible motion to compatible motion. Thus, Va becomes greater also, ultimately, being equal to the compatible axial velocity determined by the spiral angle Now. the four rollers have the same spiral anyle . So that Va is: 3.2.2 effect of circular linear velocity Deflecting driven roller No 4 to a spiral angle of +2”from the equilibrium position, the cylinder will suffer axial drifting, Fig. 8 shows the Va -Vc curve, which latter indicates that Va is directly proportional to Vc, the slope of the curve being approximately 0.00708 because 4=+2 is too small, the cylinder does not make frictional sliding against each roller. Thus, the relative axial motion between the roller and the cylinder is completely coordinated by their elastic sliding, so that Va is I. e .Va is directly proportional to Ve For the theoretical Curve the slope K * can be calculated by the following equation K”=0.25tan 4= 0.25tan2=0.00873 where K=0.00708mm/s in the experimental curve. Thus, in taking account of the experimental tolerance, the two slopes can be considered to be approximately equal. 4 Conclusions 1. Because of the deviations due to manufacturing and assembling. the cylinders central line and the rollers axis are not parallel. i. e , they are not in the same plane, and there is a spiral angle at thc point of contact between the cylinder and the roller in the circular linear velocity direction. The existence of is the basic reason for the occurrence of axial drifting. The effect of gravity in cylinders axial direction is also one of reasons for drifting. 2. The relative axial motions between an individual roller and the cylinder are composed of spiral motion. elastic sliding and frictional sliding When axial frictional sliding does not occur between the cylinder and a single roller, the relative axial motion between the rollers and the cylinder is completely coordinated by their elastic sliding, Va is directly proportional to When axial frictional sliding occurs between the cylinder and a roller. the relative asial motion between therollers and the cylinder will be commonly coordinated by elastic sliding and frictional sliding. but Va is not directly proportional to 3 The axial motions of the cylinder can be divided intocompatibleand non-compatible motion There will be large axial forces acting on the bearings of the rollers, which will cause the wear and tear of the contact surfaces of the rollers and the cylinder, when non-compatible motion exists The non-compatible component of the axial motion is undefined however. the cylinders axial velocity is always existent and definable for a particular bed, its magnitude and direction reflecting the beds inherent property. 4 The reasonable adjustment of the axial motion is to make the non-compatible component as small as possible and the compatible component as large as possible. 5 With the increment of the number of rollers deflected by the same value of the compatible component of axial velocity increases, but the non-compatible component decreases. With the increment of the compatible component, the velocity of axial drifting of the cylinder increases References (1) Z Wang(ed ). teaching material on welding machinery Equipment Gansu university of Technology lanzhou P R china (1992) pp 85-98 (2)Wuhan lnstitulcof Buildins Materials and TechnologyI Tongi Universily. Nanjing Institute of Chemical Engineering, and Huanan Institute of Technology. Cement Producing machinery equipment, Architectural Industrial Publishing House of China, Beijing, (1981) pp, 184-187 (3)J . Halling(ed.). Principles of Trilrology The Macmillan Press, (1975) pp. 174-200 关于 焊接滚轮架轴向窜动的实验研究 摘要 文章引入焊接滚轮架轴向窜动的基本理论 ,并同时在焊接滚轮架的实验模型上进行 了试验研究 . 结果表明 , 焊接滚轮架轴向窜动的主要原因在于工件的翻转存在着螺旋夹角 . 轴向相对运动产生螺旋运动 ,弹性滑动与摩擦滑动 . 其中有与理论相符的内容以及和理论不符合的内容 ,文中了轴向运动滚筒 . 他是相对于轴运动的圆筒形工件 . 相对轴的运动包括滚轮与工件相互协调的弹性滑动和摩擦滑动 关键词 :焊接滚轮架 ； 圆筒工件 ； 滚轮 ； 轴向运动 ； 螺旋角 1 介绍 在焊接生产中 ,常会遇到旋转焊接圆形工件的情况。如焊接锅炉、石油化工压力容器等 ,就必须用到 焊接滚轮架 . 进行旋转焊接时，由于制造、装配公差 ，焊接 滚轮和工件的表面平滑与否等因素 (理想的旋转工件表面是平滑的 )，使焊接不可能理想化的进行，工件必然会产生轴向窜动 。研究提供了当圆形工件焊接时，轴向窜动的机制 . 这项研究成果将有利于研究与设计反窜动焊接滚轮架 . 尤其是应用于滚轮架之上 , 并确定了制造及滚轮架的装配公差 ，为通过机械调节的方式，避免轴向窜动的方法供理论依据。调整模式采用闭环控制电路 ,并推选有价值的提案 2 理论分析 2.1 焊接滚轮架一般由四个滚轮组成 .由主动滚轮驱动 ,滚筒匀速绕轴旋转 (例 1), 其间放圆形焊接工件（如图 1） ,其中 ,s 为滚轮支架 距离 ,L 同列两滚轮距离 . Ve是圆形工件滚动的线速度 ,也被称为焊接速度 图 1 焊接滚轮架 同行的滚轮的的轴并不平行 , 从某个角度看 ,滚轮架的四辊所在的顶点组成一个简单的四边形 但如果四滚轮所在顶点不在同一平面 或因为制造及装配滚轮的圆柱是不规则的圆形 . 那么 . 工件就会在轴转动时窜动。滚轮架的滚轮与工件有一个接触点 . 假设 P为这个接触点 . 工件的标准平面的定义是一个平滑的平面 ,平面 A为圆柱母线与轴的切入点组成的平面 ,与工件相切点不在此平面内 , 一平面垂 直于平面 A切线，过 P和所在平面 B 就是滚轮的切线过相同点 P, 一般说来 , 被定义为滚轮轴和圆柱行工件的轴线的偏斜夹角 ! 定义螺旋夹角母线 N和 M. 如图 2、图 3所示，其射影线取得的突出辊母线横跨点 P 。 B定义为 N 和 M 线的投影夹角。如例 3其中三个角度关系 tan = tan2 * tan 2 轴向偏差位移矢量和射影位移矢量它们的关系是 : 图 2 滚轮和工件几何关系 图 3 个角度矢量和位移矢量的关系 2.2 轴向相对关系 (1)螺旋运动 因为滚轮轴线与中线不平行 , 在 Vr 和 Vc 之间 就有一 个螺旋角 存在 ,如图 2. 当辊筒围绕自己的轴线转动时 ,使在切线上产生摩擦力 . 因为滚轮和工件各个线速度在不同的方向，由于螺旋效应也就是窜动就会发生在点 p-滚轮和工件的接触点 (图 4). 式中： VC 是圆柱的线速 . 是工件的轴向分量 , 1.2.3.4, 分别代表四个滚轮 . (2)弹性滑动 由于存在一种螺旋角 ,在工件上产生轴向力 Faj. 当力量小于最大轴向摩擦力fnj(其中 f 是摩擦系数 ,单滚和工件正常的压力 ) 工件会下滑超过滚轮轴 23mm 的下滑速度为 . 式中 e是金属滚 轮的弹性滑动系数： e= ool0.005. (3)摩擦滑动时 faj 大于最高摩擦力 fnj, 工件将在滚轮之上做摩擦滑动 . 滑动阻力为 fnj3. 工件的摩擦滑动速度的大小和方向可确定 由环球关系工件和四滚轮摩擦滑动导致滚轮表面的磨损 . 这是意料之外的 ,在焊接进行时 ,工件发生漂移。以上三种运动不同时发生 。工件的轴向漂移速度不是代数的三个组成部分的速度 . whilst in the case of frictional sliding, the axial velocity is发生摩 擦滑动的轴向速度 2.3 工件滚轮的轴向运动 2.3.1 与理论相符的部分 在理想的条件下 , 工件和四滚轮之间的当螺旋角 j 都是一样时 ,即 : 1=2=3=4 工件的运动将与理论值相同 . 可以将两个范畴对比分析 : (1)由于重力不存在轴向分量 . 工件的轴向窜动速度 : Va=Vc * tan (2)当存在一个有重力 Ga 因素，轴向窜动速度存在一个轴力 . 现在 ,四滚轮有相同的方向 与重力 G等效的轴向窜动速度 是： 2.3.2.与理论不同的关于轴向窜动的内容 . 工件与四滚轮之间螺旋角 j 大小和方向不相等 .工件和 四滚轮的几何关系也不相同时 ,工件和四滚轮之间的轴向窜动是个不相同的 . 工件与滚轮轴向速度应该是同样的 ,因为工件被作为一个整视为一个刚体体 ,. 然而 . 有些滚轮和工件的实际上轴向速度是不完全相同的 , 所以轴向摩擦力几乎肯定会出现这种滚轮和 工件之间以下两类分类讨论不同与理论的摩擦力的大小 (一 )当轴向摩擦力确保每个滚轮和工件均低于最大轴向所需对摩擦力 滚轮和工件将产生弹性滑动单个滚轮和工件可以协调它们的弹性滑动 当工件的轴向速度是常量 , 如果忽略重力工件与四个滚轮的轴向窜动的总和将为 0 四个滚轮并 没有什么差别因此他们大致是相同的 根据上述两个方程 ,工件的轴向窜动为： 凡是 0.25 tant 范围内 .使用滚轮架的情况下 ,工件只长生产生弹性滑动 ,这可能是所谓工件 螺旋率螺旋问题 (2)当工件与滚轮的轴向摩擦力大于最大轴向摩擦力 , 工件与滚轮的圆柱体之间将发生摩擦滑动 ,这滚那 . 最大轴向力作用于滚轮轴承 Ffmax=fFNfmax 由于这种摩擦滑动的存在 . 单个滚轮与工件之间轴向传动并不协调， 现在，轴向窜动并不完全由滚轮与工件的相对关系所决定 . 很难写一个轴向传动速度的普遍相容方程 ,因为这样的条 件 很复杂 . 以下是进一步的分析和讨论这一问题时 ,首先 ,为便于分析问题 , 螺旋角定义为 而相对螺旋角度 按由大到小的顺序排列 表达为 1 2 3 4 同样的 ,滚轮与圆形工件的正常的相互作用力为 n(j). 轴向力为 Fj fNj 一般 工件的轴向运动由螺旋角的平均值 决定 工件的轴向窜动 ,由相对螺旋角的定义窜动为不完全的组成部分 , 当圆柱体沿着轴向，恒定速度 ，其速度表示分析表明 asVan 是平