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~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 fric-tional 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.