Abstract:

Due to the comprehensive effect of the characteristics of pure electric vehicle， such as fast acceleration， large mass， high requirements for braking force and large demand for braking heat dissipation， the commonly used ventilated disc brake system will produce a low?frequency noise perceivable from high speed to low speed， which will significantly affect the comfort of passengers in the vehicle. In this paper， the vehicle and system level analysis of this kind of braking noise is carried out and the mechanism hypothesis that the displacement fluctuation of the ventilated disc causes the surface vibration and leads to the interior noise is proposed. The hypothesis is verified by numerical simulation. Then， the key parameters that influence the ventilated disc displacement fluctuation is studied and it shows that the span of heat dissipation rib is the core optimization parameter， and the empirical value of the displacement fluctuation is given. Based on this， the comprehensive optimization solution is put forward， which is verified by simulation， vehicle sample test and subjective evaluation. The results show that the optimized sample can completely solve the problem of braking noise and also the effectiveness of key design parameters are proven， which lays a basis for ventilation disc design and multi parameter optimization of various types of electric vehicles.

Key words: electric vehicle, NVH, braking noise, braking disc, ventilated disc