| At present,while developing high-speed railways,China has also accelerated the construction of heavy haul railways.Heavy haul transportation technologies are mainly developed from the aspects of increasing the axle load of heavy haul freight vehicle and increasing the length of train formation.However,with the increase of axle load of heavy haul freight vehicle,requirement of locomotive traction and braking force increase,while a big increase in length of the train can cause brake when the train brake wave extended further,leading to significant increase in the longitudinal impulse to the train,and may even threaten the safe operation of the train.Founded in practical operation,for example,the HXD2 new eight-axle heavy haul locomotive has obvious lateral displacement and large rotation of the coupler under braking conditions.This is a typical heavy haul train longitudinal impulse problem.Under this background,in order to provide a technique solution for inhibition of car body lateral displacement measures,based on vehicle system dynamics theory,the influence of the secondary lateral stop parameters on lateral dynamic performance of heavy haul locomotive car-body and coupler/draft gear system was studied by means of dynamic simulation analysis and field test.First of all,on the basis of analyzing the structural characteristics and stable mechanism of 13A/QKX100 coupler/draft gear system,the important factors affecting the stability of the car-body under the braking force was focused on.It is pointed out that the bogie spacing,the lateral stiffness of primary suspension systems,the lateral stiffness of secondary suspension systems,the stiffness of the secondary lateral stopper,the free clearance and elastic clearance of the secondary lateral stopper are important parameters affecting the stability of the car-body.The selection of the secondary lateral stopper parameters is the research object of the influence factors of the lateral dynamic performance of the heavy haul locomotive car-body and coupler/draft gear system.Using the SIMPACK multi-body dynamics analysis software,a train dynamic model including two sets of eight–axle heavy haul locomotives,a dummy freight vehicle and 13A/QKX100 coupler/draft gear system was built.The comparisons including the coupler force,the coupler angle and the car-body’s lateral displacement between the calculated results and the tested results were made to verify the effectiveness of the train dynamic model.In summary,this model can be used to simulate the dynamic performance of the heavy haul locomotive and its coupler/draft gear system.The influence of the secondary lateral stopper on the coupler angle,the car-body’s lateral displacement and the safety index of locomotive was studied.Two kinds of optimizations are proposed through the analysis of secondary lateral stopper parameter matching.The two optimizations are the free clearance of the secondary lateral stopper is 10 mm with the stiffness is 5 times of the original one(optimized program 1),and the free clearance of the secondary lateral stopper is 20 mm with the stiffness is 5 times of the original one(optimized program 2)respectively.Through the dynamic analysis of the optimization program locomotives and the behavior of heavy haul locomotive under braking condition through the operation of the small radius curve.Drawing the conclusion that: the safety index of locomotive under both optimizations meet the requirementsAt last,a field dynamic test was conducted on both of the secondary lateral stopper optimizations at the internal connection line of the CRRC Corporation.The measured results indicate that both the two optimizations reduce the coupler angle and the car-body’s lateral displacement,and the coupler compressive stability capacity of the two optimizations is improved.In addition,the effect of optimization program 1 is better than that of optimization program 2. |
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