DTVI2型扣件螺旋道钉折断研究及整治实践

Research and Treatment Practice on DTVI2 Coupler Screw Spike Fracture

DTVI2型扣件采用DI型弹条、T30型螺旋道钉。根据近年来各地铁运营线路设备设施表现,螺旋道钉折断为DTVI2型扣件主要病害之一。螺旋道钉折断导致扣件系统失效,钢轨约束力减少,线路几何形位变化,影响列车运行。此外,折断的螺旋道钉不仅拆卸、更换困难(需通过热熔、水钻等方式拆卸),而且折断螺帽容易遗留在钢轨轨底,造成钢轨联电打火,影响安全运营。通过对北京地铁14号线DTVI2型扣件螺旋道钉折断地段线路线形、道床形式分析,小半径曲线、钢弹簧浮置板道床地段DTVI2型扣件螺旋道钉更易折断。通过材料力学及ANSYS有限元模型分析,螺旋道钉肩胛处应力集中、扭矩超标为其折断主要原因。通过螺旋道钉加装重型弹簧垫圈,有计划地进行螺旋道钉拆解涂油,调整扭矩值,改善扣件工程状态,降低DTVI2型扣件螺旋道钉折断发生,确保扣件系统安全可靠。

The DTVI2 type coupler adopts DT type spring strip and T30 type screw spike.According to the performance of equipment and facilities of each metro line in operation in recent years,screw nail fracture is one of the main diseases of DTVI2 coupler.The screw stud breakage which leads to the failure of coupler system,the reduction of binding force,the change of line geometry will influence the train operation.In addition,broken screw nails are difficult to dissemble and replace(need to be disassembled by hot melting,injection drill,etc.);and the broken screw cap is easy to be left at the bottom of the rail,rail connecting ignition,affecting the safe operation.Through the analysis of the line shape and roadbed form of the broken section DTVI2 type coupler screw stud of Beijing Metro Line 14,the DTVI2 type coupler screw nails are easier to break in the section with small radius curve and steel spring floating plate bed.Through analysis of material mechanics and ANSYS finite element model,the stress concentration and torque exceeding the standard at the shoulder blade of spiral screw nail are the main causes of its fracture.Through adding heavy spring washer in helical stud,planned removing and oiling the screw spike,adjusting the torque value,improving the engineering state of fastener,the screw stud break of DTVI2 coupler will reduce,ensuring the safety and the reliability of coupler system.