某柴油发动机弹性联轴器撕裂故障分析及优化

时胜文^1,2，刘杰^1,2，王慧辉^1,2，张中业^1,2，徐可鹏^1,2

1.内燃机与动力系统全国重点实验室，山东 潍坊  261061；2.潍柴动力股份有限公司，山东 潍坊  261061

摘要：为解决某柴油发动机台架试验过程中飞轮端弹性联轴器橡胶体频繁撕裂故障，开展轴系扭转振动测试试验和弹性联轴器橡胶体温升试验，分析飞轮端弹性联轴器失效原因；基于AVL Excite Designer软件，建立了台架一维轴系当量简化模型并进行扭振仿真分析；采用增大测功机端弹性体与万向轴万向节间转动惯量的方法进行优化，并结合仿真分析和台架试验进行验证。结果表明：轴系第1阶扭振频率与发动机第2阶激励频率发生共振，导致弹性联轴器橡胶体扭转角振动过大，造成其扭转疲劳撕裂和过热熔化，最终导致橡胶体失效；由于测功机转动惯量大于发动机转动惯量，因而飞轮端弹性联轴器橡胶体的相对扭转角大于测功机端的相对扭转角，使飞轮端弹性联轴器橡胶体耗散功率大于测功机端，导致飞轮端弹性联轴器橡胶体更容易失效；通过增大测功机端弹性体与万向轴万向节间转动惯量，可使轴系第1阶扭振共振频率避开发动机常用转速区，同时飞轮端弹性联轴器橡胶体的耗散功率减小了33%，延长了联轴器橡胶体使用寿命，有效解决飞轮端弹性联轴器橡胶体频繁撕裂的问题。

关键词：弹性联轴器；扭转振动；相对扭转角；耗散功率

Failure analysis and optimization of elastic coupling tear for a diesel engine

SHI Shengwen^1,2, LIU Jie^1,2, WANG Huihui^1,2, ZHANG Zhongye^1,2, XU Kepeng^1,2

1.State Key Laboratory of Engine and Powertrain System, Weifang 261061,China; 2.Weichai Power Co., Ltd., Weifang 261061,China

Abstract: To address the frequent tearing failure of the rubber body of the elastic coupling at the flywheel end during the bench test of a diesel engine, torsional vibration tests of the shafting system and temperature rise tests of the rubber body of the elastic coupling are carried out to analyze the failure of the elastic coupling. Based on the AVL Excite Designer software, a 1D equivalent simplified model of the bench shafting system is established, and torsional vibration simulation analysis is conducted. An optimization method is adopted by increasing the moment of inertia between the elastomer at the dynamometer end and the universal joint of the cardan shaft, and the effectiveness is verified through simulation analysis and bench tests. The results show that resonance occurs between the first-order torsional vibration frequency of the shafting system and the second-order excitation frequency of the engine, leading to excessive torsional angle vibration of the rubber body of the elastic coupling, which causes torsional fatigue tearing and overheating melting of the rubber body, and finally results in the failure of the rubber body. Because the moment of inertia of dynamometer is greater than that of engine, the relative torsion angle of the rubber body of the elastic coupling at the flywheel end is greater than that at the dynamometer end, so the dissipated power of the rubber body of the elastic coupling at the flywheel end is greater than that at the dynamometer end, which leads to the elastic coupling at the flywheel end being more prone to failure. By increasing the moment of inertia between the elastomer at the dynamometer end and the universal joint of the cardan shaft, the first-order torsional vibration resonance frequency of the shafting system can be shifted away from the common speed range of the engine. Meanwhile, the dissipated power of the rubber body of the elastic coupling at the flywheel end is reduced by 33%, which prolongs the service life of the coupling rubber body and effectively solves the problem of frequent tearing of the rubber body of the elastic coupling at the flywheel end.

Keywords: elastic coupling; torsional vibration; relative torsional angle; dissipated power