Study On Vibration Comfort Of Heavy-duty Commercial Vehicle Cab

With the rapidly development of national economy,the greatly growth of heavy-duty commodity exchange,and the broadly construction of high-ways,the commercial using of the automobiles has been resulting a booming increasing at the present time. Commercial vehicle is becoming the main instrument of the high-way transportation. At the same time,as the improvement of the automotive technology, people's life standards and national road pavement,the customers claim for higher vibration comfort,which is one of the most important properties of the commercial vehicle.Based on the road-test and taking advantage of the multi-body dynamic model,the aim to improve the vibrate comfort of the commercial vehicle was set from the following two perspectives: the cab structure and the cab suspension.When objectively analyzing the result of the road-test,we found that it is necessary to improve the vibrate comfort and we also get the excitation and validation signals.On the improvement of the cab structure,the finite element model is firstly established. And then the static stiffness and modes are analyzed. Finally, an optimum structural design were built,which has led to the twist stiffness of the cab improved 19% and the first mode improved 2.9 Hz.,The previous and newly built finite element model were imported in the ADAMS respectively to build a coupling dynamics model and make a quantitative contrast of the vibrate comfort on the basis of the excitation signals from road test and the appreciation of the acceleration RMS. The results show that at various vehicle speeds,the weighted acceleration RMS was all reduced at the seat in the cab,the reduction is 6.2% at 60km/h.With the improvement of the suspension parameters,a multi-body dynamics model based on flexible cab was built. Taking the acceleration RMS as an evaluation target,the orthogonal test for optimizing the stiffness and damping of the suspension was conducted in the frequency domain. The different dynamic deflections were compared in time domain. At various vehicle speeds,acceleration RMS of the driver's seat was all reduced after optimization of the cab suspension,the reduction is 9.6% at 60km/h. And the dynamic deflection of the suspension has also had a 21% reduction on average. Through the improvement of the cab structure,the improvement of the suspension parameters,the vehicle cab could meet the requirements of vibration comfort better.