某水电站筒形阀接力器机械反馈滚珠丝杆断裂失效分析  

Analysis on Fracture of Servomotor Ball Screw of a Cylindrical Valve in a Hydropower Station

作　　者：彭以超 王贤明 干建丽 赵炜炜 

机构地区：[1]浙江浙能技术研究院有限公司,杭州310003 [2]浙能北海水力发电有限公司,浙江丽水323900

出　　处：《浙江电力》2016年第12期30-35,共6页Zhejiang Electric Power

摘　　要：以断裂的筒形阀接力器滚珠丝杆为研究对象,对丝杆断裂部位进行了包括化学成分、表面渗碳情况、不同部位的金相组织、断口裂纹源及扩展路径、力学性能、接力器运行状态等一系列分析,进而综合讨论滚珠丝杆的失效机理。发现造成滚珠丝杆发生弯曲断裂的直接原因是接力器下腔的压缩空气未排除干净,压缩空气的瞬间爆破造成瞬间反馈丝杆轴向窜动量增大,端部主、从动齿轮耦合咬死,使得丝杆瞬间无法旋转,在轴向的压力和扭矩下丝杆发生弯曲和断裂。另外,滚珠丝杆通过渗碳来增加表层硬度,表层硬度最高可达743 HV,组织为针状马氏体,表层高硬度造成丝杆脆性较大,脆性表层容易萌生裂纹并迅速扩展发生断裂。By research on the fractured servomotor ball screw of a cylindrical valve, the paper analyzes the fracture in terms of chemical composition, case carburization, and metallographic structures, crack initiation,propagation path, mechanical property of different parts and servomotor operation performance; furthermore,it discusses failure mechanism of the ball screw. The final result shows that the fracture was caused by the left compressed air in the lower servomotor cavity. The instantaneous blast of compressed air caused sudden axial displacement increase of the screw and final locking of the driving and driven wheels on the screw end, so the screw bended and broke finally due to torque and axial pressure. What＇s more, the ball screw is carburized to increase the surface hardness, which is up to 743 HV and the structure is needle-shaped martensite.The great surface harness results in screw brittleness, and the brittle surface may easily crack and fracture with its propagation.

关 键 词：筒形阀 接力器 滚珠丝杆 断裂 失效分析 

分 类 号：TV734.1[水利工程—水利水电工程]