Abstract:

In order to optimize the balance shaft gear rattle noise of the longitudinal hybrid vehicle, by comparing the structural differences with the transverse hybrid vehicle, it is identified that the increase of the inertia of the flywheel, the decease of the crankshaft mode, and the increase of the drive gear angular acceleration of the balance shaft lead to the gear rattle of the balance shaft. However, the conventional single-stage TVD matching presents the law of "one thing decreases and the other grows", which cannot cover the optimization objective of the angular acceleration of the engine at the full speed segment. Therefore, a two-stage TVD is developed to reduce the angular acceleration of the drive gear of the balance shaft, which can solve the problem of gear rattle. The Simpack software is used to build a multi-body dynamic model of gear rattle, which studies the mechanism of gear rattle generation and propagation of the balance shaft. Then a double anti-backlash balance shaft is developed to further optimize the noise of gear rattle by reducing the force impact on both sides of the gear teeth during meshing. The results show that the combined use of two-stage TVD and double anti-backlash balance shaft can solve the gear rattle problem, which has important engineering significance for the design of the balance shaft gear and the optimization of rattle problem.

Key words: balance shaft, gear rattle, two-stage TVD, Simpack, multi-body dynamics