It is well known that in the automotive field, as well as in other fields, there is an increasing demand for components producing low levels of noise and vibrations, due to comfort reasons. This is consequently one of the main problems for the suppliers of automotive components, which are forced to increase their knowledge on the dynamic behaviour of their products; to this end, mathematical models can be very useful tools for the identification of noise and vibration sources, and to predict the effects of design modifications and so reducing the number of tests required for design improvement. This work concerns external gear pumps for automotive applications, which operate at high speed and low pressure. In this situation gear pumps have two main noise sources both of them sharing the same fundamental frequency: fluid borne noise, as a consequence of the flow from the low to the high pressure chambers, and mechanical noise due to the gear meshing. In this context, a combined non linear lumped/finite element model including the main important phenomena involved in the pump operation as time-varying oil pressure distribution on gears, time-varying meshing stiffness and hydrodynamic journal bearing reactions has been developed. The model was experimentally validated by using a non standard methodology based on the comparison between simulations and experimental results concerning accelerations, forces and moments. Therefore the model can be used in order to analyse the pump dynamic behaviour and to identify the effect of design and operational parameters, in terms of vibration and dynamic forces.
Dynamic analysis of external gear pumps by means of non linear models and experimental techniques
MUCCHI, Emiliano
2007
Abstract
It is well known that in the automotive field, as well as in other fields, there is an increasing demand for components producing low levels of noise and vibrations, due to comfort reasons. This is consequently one of the main problems for the suppliers of automotive components, which are forced to increase their knowledge on the dynamic behaviour of their products; to this end, mathematical models can be very useful tools for the identification of noise and vibration sources, and to predict the effects of design modifications and so reducing the number of tests required for design improvement. This work concerns external gear pumps for automotive applications, which operate at high speed and low pressure. In this situation gear pumps have two main noise sources both of them sharing the same fundamental frequency: fluid borne noise, as a consequence of the flow from the low to the high pressure chambers, and mechanical noise due to the gear meshing. In this context, a combined non linear lumped/finite element model including the main important phenomena involved in the pump operation as time-varying oil pressure distribution on gears, time-varying meshing stiffness and hydrodynamic journal bearing reactions has been developed. The model was experimentally validated by using a non standard methodology based on the comparison between simulations and experimental results concerning accelerations, forces and moments. Therefore the model can be used in order to analyse the pump dynamic behaviour and to identify the effect of design and operational parameters, in terms of vibration and dynamic forces.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
