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西南交通大学硕士研究生论文 第
I
页
摘 要
随着我国经济的快速发展,铁路已经跨入了全面推广无缝线路的新时代。闪光焊
作为无缝线路现场钢轨焊接的首选方式,其加热主要通过短路液桥电阻热实现,因而
液桥存在的时间就影响着钢轨的加热与端面状态,而液桥存在时间又受焊机动夹动态
性能的影响。由于钢轨焊接工艺试验时不可能采用现场施工的长钢轨进行,并且现场
施工工况千差万别,因此目前采用短轨调试获得的焊接工艺用于现场焊轨对钢轨焊接
接头的质量是有影响的,但这种影响有多大,又是如何影响的,目前未见报道,为此,
开展现场工况对焊接接头质量的影响研究具有很好的实际应用价值。
针对现场钢轨闪光焊的具体现场施工工况,以国内广泛应用的
UN5-150ZB
焊机
控制系统为基础,在 MATLAB 环境下采用 SimHydraulics 软件建立了闪光焊机机头液
压系统仿真模型,在此基础上,分别针对油路系统的不同结构参数以及负载变化等情
况,对动夹的动态响应特性进行了仿真分析,仿真结果表明:随着液压油管的直径以
及油管长度的增加,动夹的动态响应速度会相应的减小;现场焊接时坡度的存在会对
动夹送进和后退时的动态响应产生影响,但当动夹以相同的送进速度和后退速度做周
期性运动时,坡度对动夹动态响应产生的影响基本可以近似抵消;所垫滚筒类型的摩
擦系数以及动端钢轨质量变化较大时对动夹的动态响应速度影响较大,随着摩擦系数
及钢轨质量的增加,动夹的动态响应速度会大大降低;而增大机头油压压力以及比例
阀的输出流量能够提高动夹的动态响应速度。
在上述仿真结果的基础上,提出了焊机优化油路设计和改变控制策略以提高焊机
动态性能的措施:可以通过减小现场钢轨闪光焊机机头液压系统的换向阀或比例阀 A、
B
口连接的油管直径和油管长度来提高焊机动夹的动态响应速度;当焊接环境及钢轨
质量变化时,可以通过采用合理的控制算法对机头液压系统油压和比例阀的输出流量
进行控制以及减小钢轨与滚筒之间的摩擦系数来提高动夹的动态响应速度,从而减少
现场焊接工况的变化对焊接质量的影响,为现场焊接质量的保证提供了方向。
关键词:闪光焊;液压系统;动态响应;
SimHydraulics
仿真
西南交通大学硕士研究生论文 第
II
页
Abstract
With the rapid development of Chinese economy, the railway has stepped into the new
era of the comprehensive promotion of jointless track. Flash welding is the preferred way of
rail welding on jointless track. The heating of flash welding is mainly achieved through the
resistance heat of a short circuited liquid bridge, so the liquid bridge existing time affects
the heating and end surface's state of the rail. However, the existence time of the liquid
bridge is influenced by the dynamic performance of the movable clamp of welder. Due to
the welding process test of rail is impossible to use on-site long rail, and the field working
conditions are varied, therefore, the welding process obtained by short rail debugging is
applied to rail welding on the spot, which has an influence on the quality of rail welded
joints. But how to affect the welding quality and the extent of its impact have not been
reported. Therefore, it is of great practical application value to study the influence of field
conditions on the quality of welded joints.
Aiming at the specific field construction condition of rail flash butt welding, based on
the widely used UN5-150ZB welder's control system in domestic, under the environment of
MATLAB, using SimHydraulics software established the simulation model of the hydraulic
system of flash welder’s handpiece. On this basis, the dynamic response characteristics of
the movable clamp are simulated and analyzed in the case of different structural parameters
of the oil system and the load fluctuation. The simulation results show that with the increase
of the diameter and the length of the tubing, the dynamic response speed of the movable
clamp will be decreased correspondingly. The existence of the slope will affect the dynamic
response of the moving clamp, but when the feed speed and the reverse speed of the
movable clamp are the same, the influence of slope on dynamic response of movable clamp
can be approximately eliminated. The change of the friction coefficient and the rail quality
have great influence on the dynamic response speed of the moving clamp. With the increase
of the friction coefficient and the rail quality, the dynamic response speed of the movable
clamp will be greatly reduced. And the dynamic response speed of the movable clamp can
西南交通大学硕士研究生论文 第
III
页
be improved by increasing the oil pressure and the output flow of the proportional valve.
On the basis of the above simulation results, the measures of optimizing the oil circuit
design and changing the control strategy to improve the dynamic performance of the welder
are put forward. The dynamic response speed of the movable clamp can be improved by
reducing the diameter and the length of the tubing connected to the A and B ports of the
directional valve or the proportional valve. When the welding environment and rail quality
change, the dynamic response speed of the movable clamp can be improved by reducing the
friction coefficient between the rail and the roller and using a reasonable control algorithm
to control the oil pressure of the handpiece hydraulic system and the output flow of the
proportional valve, so as to reduce the influence of the welding conditions on the welding
quality. And it provides direction for on-site welding quality assurance.
Key words: flash welding; hydraulic system; dynamic response; SimHydraulics simulation
西南交通大学硕士研究生论文 第
IV
页
目 录
第
1
章 绪论
.............................................................................................................................1
1.1 课题的研究背景........................................................................................................1
1.2 液压系统仿真技术研究现状................................................................................... 3
1.3
课题主要工作内容及意义
....................................................................................... 8
第 2 章 闪光焊工艺及设备.................................................................................................... 9
2.1 闪光焊原理及工艺过程........................................................................................... 9
2.1.1
闪光焊基本原理
.............................................................................................9
2.1.2 闪光焊工艺过程.............................................................................................9
2.2 UN5-150 钢轨闪光焊机简介.................................................................................. 11
2.2.1
焊机总体布局
...............................................................................................11
2.2.2 焊机机头及吊架...........................................................................................13
2.2.3 焊机电气控制系统.......................................................................................14
2.2.4
焊机液压控制系统
.......................................................................................15
2.2.5 焊机冷却回路系统.......................................................................................17
2.3 本章小结..................................................................................................................18
第
3
章 闪光焊机机头液压系统仿真模型建立
.................................................................. 19
3.1 MATLAB/SIMHYDRAULICS 仿真工具简介.............................................................19
3.2 顶锻系统各模块 SIMHYDRAULICS 模型的建立.................................................... 20
3.2.1
液压源模块
SimHydraulics
模型
................................................................ 20
3.2.2 顶锻油缸模块 SimHydraulics 模型............................................................ 22
3.2.3 伺服电磁阀模块 SimHydraulics 模型........................................................ 23
3.2.4
电磁换向阀模块
SimHydraulics
模型
........................................................ 35
3.2.5 负载及检测模块 SimHydraulics 模型........................................................ 37
3.2.6 溢流阀及液压管 SimHydraulics 模型........................................................ 38
3.3
闪光焊机液压系统仿真模型
................................................................................. 39
3.4 本章小结..................................................................................................................40
第 4 章 闪光焊动夹动态响应特性仿真结果及分析.......................................................... 41
4.1
不同油路结构参数下动夹动态响应特性仿真分析
............................................. 41
4.1.1 油路内部阻力对动夹动态响应特性仿真分析.......................................... 42
4.1.2 不同管长下动夹动态响应特性仿真分析.................................................. 43
4.1.3
不同管径下动夹动态响应特性仿真分析
.................................................. 45
4.2 不同现场工况下动夹动态响应特性仿真分析..................................................... 48
西南交通大学硕士研究生论文 第
V
页
4.2.1 不同动端钢轨质量下动夹动态响应特性仿真分析.................................. 48
4.2.2 不同坡度及摩擦系数下动夹动态响应特性仿真分析.............................. 50
4.3
本章小结
..................................................................................................................54
第 5 章 闪光焊机动夹动态响应速度控制研究................................................................ 55
5.1 不同压力及流量下动夹动态响应特性仿真分析................................................. 55
5.2
动夹动态响应速度控制研究
................................................................................. 58
5.3 本章小结..................................................................................................................62
结论.........................................................................................................................................63
参考文献
.................................................................................................................................64
致谢.........................................................................................................................................68
攻读硕士期间发表的论文及科研成果................................................................................ 69
剩余73页未读,继续阅读
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