基于有限元的锁紧螺母动态响应分析

Study on Dynamic Characteristic of Tightened Structure Nut based on Finite Element Analysis

以某液力机械行星变速结构涡轮轴紧固机构为研究对象,开展基于有限元的扭转振动激励对于紧固件预紧力和内部接触力变化规律的研究.通过建立有限元模型,分析在不同预紧力作用下螺母的轴向位移幅值变化规律和垫片止动舌与螺母、垫片内止动舌与螺纹轴的接触力的变化规律.由仿真结果可知:预紧力越小,螺母的轴向位移幅值在输入轴的扭转激励作用下逐渐增大的趋势越快,紧固件松动的趋势也越快.垫片止动舌与螺母、垫片内止动舌与螺纹轴的接触力出现周期性变化,随着紧固件的松动,其接触力幅值逐渐增大,止动舌受到疲劳断裂的机率增大.

Targeting at screw thread of tightened structure on turbine shaft in a certain hydraulic mechanical planetary gear box,the tightening torque and contact force of screw under strong torsion was studied based on FEM.A FEMmodel for torsional vibration was investigated to study the law of nut axial displacement,the contact force between thrust and screw shaft,thrust and nut.Simulation result shows that as the value of tightening force become smaller,the axial displacement of nut under the same torsional vibration grows bigger,and the tighten structure looses faster.The contact force between thrust and screw shaft,thrust and nut changes periodically.If the tighten structure looses,the contact force will be bigger,and the fatigue crack risk of thrust will also increase.