Abstract
Factors affecting meshing noise in a silent chain were studied using a multibody dynamics simulation. In order to predict chain noise using the simulation, it was necessary to specify chain system behaviors that had a strong correlation with noise. Prior to the simulation, tests were therefore conducted in order to measure meshing noise and the behavior of each part of the chain system, and chain system behaviors displaying a high correlation with noise were identified. A balancer drive chain for a 4-cylinder gasoline engine was used in the tests. In order to exclude the effect of other parts as much as possible, the tests were conducted after parts including the pistons and the camshaft drive chain had been removed to leave only a simple mechanism consisting of the crankshaft and the balancer system. A correlation was observed between the measured noise and chain behavior. Next, the measurement results were compared with the results of a multi-body dynamics simulation of the chain behavior correlated with noise. The simulation used a link-by-link model that expressed meshing for each link of the chain. Because the shapes of the chain link plates and the sprockets have a significant effect on meshing behavior, the shapes of these parts were precisely measured, and the measurements were reflected in the simulation. The results of predictions using the model and actual measurement results were compared. These comparisons demonstrated that the tendency of changes in meshing noise could be accurately predicted using the simulation. Next, the mechanism of generation of chain noise was theorized, the factors with a significant effect on chain noise were isolated, and their effect was studied using the simulation. As a result, it was predicted that the weight of the chain would have a significant effect on meshing noise.
Keywords: chain noise, silent chain, simulation, multi-body dynamics, polygon effect