Design And Analysis Of The Engine Timing Silent Chain System And Experimental Study On High-speed Characteristics

This paper is supported by Jilin Province Science and Technology DevelopmentProgram (20116004)“Key Techniques of Hybrid Cars with the Chain TransmissionSystem”, and the NSFC Project (51305154)“Bipolar Drive Hy-Vo Multiple Variantsof Tooth Shape Chain System and the Meshing Mechanism Research”. Based on themeshing principles of silent chain and the design parameters input condition providedby engine manufacturer, the timing silent chain driving system and oil pump chaindriving system are built. Depend on the multi-rigid-body dynamic analysis and therigid-flexible multi-body dynamic analysis knowledge, characteristics are analyzed.Through the relevant road high-speed characteristics test, chain wear elongation iscalculated. The wear mechanisms are researched by wear morphology of chain plateand pin.Firstly, the importance and recent status of silent chain is described systematicallyat home and abroad. According to the design parameters, based on the meshingprinciple and design method of silent chain, the geometric model and thethree-dimensional model of timing round pin silent chain driving system and oil pumpchain driving system, including chain plates, plates, round pins, sprockets, fixed guide,tensioning guide, etc, are built in this paper. The trajectory of the chain, the tensionforce between chains, the contact force, the transmission ratio and rotational speed ofchain plates are tested by multi-rigid-body dynamics analysis. The results show thatthe system has good transmission characteristics, and the influence on transmissionerror caused by polygon effect is also small.The contact force between link-plate with the sprockets and pins of system modelare tested and the different nodes at different profiles are also analyzed through therigid-flexible multi-body dynamic analysis. The results show that the stress can meetthe design requirements, at the same time, chain plate can effectively realize theinner-outer compound meshing mechanism. The time of the internal meshing and theexternal meshing is almost the same, and this can reflect good transmissionperformance. During the rigid-flexible dynamic analysis, new methods of modelingand analysis closer to actual working condition is firstly adopted, getting thesimulation results more accurate and more scientific and providing theoretical supportand inference for wear mechanism research.Based on the structure of one automobile engine, timing round pin silent chaindriving system are tested through road high-speed characteristics test. To guaranteethe accuracy of the test results, the conditions of the road test must be standardized.The wear elongation of timing chain system and oil pump chain driving system areanalyzed through the measurement of links. The results show that wear elongationsmeet the design requirements. The microscopic morphology on the worn surface of plates and pins are analyzed by XL30W/TMP scanning electron microscope and thedifferent wear mechanisms are studied. Analysis results show that the wearphenomenon is not caused by one certain wear mechanism, but by several types’interaction effects. The main wear mechanism is different between chain plates andpins. This is maybe due to the different working condition between chain plates andpins.Above all, the design, simulation analysis and road test of timing round pin silentchain and oil pump silent chain driving system provided in this paper can effectivelyshorten the design cycle, and it is of significance to improve engine silent chaindevelopment and application.