Research on engine timing bush chain meshing noise optimization

SHI Shengwen; ZHANG Zhongye; WANG Xianyu; DOU Yanfei; LIU Hongwei

doi:10.16578/j.issn.1004.2539.2026.06.018

Abstract：[Objective]Aiming at the prominent meshing noise of the timing bush chain in a certain type of engine,noise reduction schemes were proposed from the perspective of sprocket tooth profile optimization to reduce meshing noise and improve the NVH performance of the chain system,so as to provide a reference for the noise optimization design of similar chain drives.[Methods]Firstly,the two core noise generation mechanisms of the bush chain,namely meshing impact and polygon effect,were analyzed to clarify the optimization direction.Secondly,based on GB/T 1243-2024 standard,two tooth profile optimization schemes were put forward,including increasing the tooth space angle to reduce the meshing pressure angle and reducing the sprocket pitch while keeping the chain pitch unchanged,to suppress meshing impact and polygon effect respectively.Then,a multi-body dynamic model of the chain system was established by using RecurDyn software,and the bush-sprocket contact force and longitudinal displacement of chain links under different schemes were simulated and analyzed to quantify the optimization effect.Finally,test verification was carried out in the engine hemi-anechoic chamber,and the meshing order sound pressure level at different rotating speeds was measured to confirm the effectiveness of the schemes.[Results]The results show that the low pressure angle scheme reduces the meshing-in contact force of the camshaft sprocket by up to 13.5%,and the low pitch scheme reduces the meshing-in contact force by up to 7.7%and the fluctuation of the longitudinal displacement of the free chain link by up to 22%;both schemes can reduce the 28th-order meshing noise by 8-10 dB(A).The low pressure angle scheme has better performance in the low-speed range,while the low pitch scheme achieves more significant improvement in the medium and high-speed ranges.