CVT GEAR NOISE IN THE HYBRID CAR DRIVE TRAIN

摘要

The hybrid passenger car of the Technical University of Munich contains a complex i{sup}2-CVT-gearbox with one PIV-chain CVT-stage, six spur gears and internal clutches. This paper presents a method to access its noise emission and to identify important sources based on design parameters. A multibody system model of the gearbox and the entire drive train as set up on the testbed is built. Excitation mechanisms like impact and frictional forces between rocker pins of the chain and the discs of the CVT as well as toothing forces are modelled in detail by complex nonlinear stiffness functions. A method to calculate the A-rated equivalent continuous force level of the bearing forces, which is proportional to the sound is presented here. As it is based on a Fourier transform of the bearing force trajectories, the influence of excitation mechanisms on structural borne sound can be shown and confirmed by measurement.